I'm sort of torn on the subject.
I remember Final Fantasy 6 fondly for the hidden Elixirs and the other items. At the time the game was released and I had played it, it was a new concept to me that treasures were anywhere except chests. That, if I just looked around and clicked on things, I could get free stuff. It made me feel clever and smart and whatever else because I clicked on things and was rewarded with stuff for clicking on things.
Then, I played a lot more RPG's.
I, honestly, don't care so much about the "hidden items" anymore. I'm actually with @kirbwarrior
to an extent here. If I click a pot in a game and it gives me something, I suddenly have a growing unease of, "wait, this pot contained something... does EVERY pot contain something? I have to click on every single pot in the game now? What else might be hiding items?"
That sudden unease just comes from the imagined wastes of time ahead of me. I want the loot because... lizard brain has to have all the shinies. I can't just... NOT loot something!
But, knowing this has lead me to just... not checking if items are hidden in things. I'm often avoiding the "hidden items" just because I know that once I click one and find out it contains an item... I am now trapped and obligated
to check absolutely everything. All the time. I just... I can't. No. I don't find being trapped by the promise ot loot to be "fun". Especially since, personally, I hate when any game says, "Here's a game of hide and seek!" for any reason (yes, even games that give you a huge circle for you to search for someone or something within to progress a quest... I don't have time for this and I don't find it fun. I find it to be padding most of the time. I am not one of those oldschool gamers who looks fondly upon games that made me have to keep notes, make maps, and find things on my own. I absolutely love quest markers in all their immersion breaking glory because at the very minimum, they keep me from getting bored and annoyed).
As I have gotten older, I have sort of shifted what I like in terms of "extra items". I like when the game tells me, "item here, click it" more often. It means the devs are often not keen on wasting my time. They don't want me clicking on everything. They tell me straight up, "here's some stuff, click it if you want it".
After all, now that my time for gaming is far more limited, I have to use that time more wisely. Is it fun to know that I've spent hours clicking thousands of random objects (pots, jars, clocks, tables, bookshelves, etcetera) only to get nothing for doing so? Is that "fun" exploration? I guess I don't find it to be fun or exploration.
See, if we're talking about "loot in the wild", we're inevitably talking about "exploration" in the game world. At which point, you need to define, as the dev, what "exploration" looks like to you in your game. Then, you need to tell your game players that your definition of "exploration" might not be the same as theirs.
If you create a game like Skyrim that is basically just an Immersive Sim, then it makes sense to have items everywhere, a lot hidden, and nothing to advertise there was anything there. After all, that feature plays into "Immersing" the player in the experience of that world. Of course the bandits hid treasure in that pot buried under 30 other pots. They were counting on nobody wanting to dig through all the pots for the one that holds their valuables. This is exploration in the Immersive Sim. Where and how an item was obtained are often small snippets of storytelling on their own. Or, even, characterization if you're lucky.
But, if you have a top/down RPG that is very much mostly just using RPG conventions... It's a lot less "exploration" and more "a checklist". "Did I click all the pots in this room? Yep. Okay, done."
I think what we should also examine is whether or not there's value in having these instances of "wild loot" as well.
Let me ask a simple question:
"When was the last time you clicked one of these 'wild loot' locations and was truly excited or happy by what you received?"
For me, that tends to be the issue. I'm clicking these things because they're there. Because I know they're there. Just like I can't leave a Treasure Chest unopened. I HAVE to open them all. I HAVE to see what's inside.
But, is that enough for a player to "enjoy" the experience? I don't know. I know that I personally don't like it. I, personally, find little enjoyment in it.
"Got a Potion!". Thanks, I've already got 50 of them that I'll never use.
"Got 3,000 G!". Thanks, add it to the pile of money I can't ever spend.
"Got 4 Reagents!". Thanks, but these aren't even valuable, these are common, and I haven't crafted their recipes for hours at this point.
On an on. At least, for me, that's not interesting. It's not exciting. I'm not finding "something of value", I'm "ticking a box". There's a sparkly in this room, so I clicked it to tick the box.
For me, when you reduce exploration to "ticking a box", it just ceases to be exploration anymore. I love exploration. I love finding hidden things. I found the Sword of Dead Kings in this hidden room! Awesome! I solved a puzzle and was given access to room full of Lore and a couple high tiered Consumables (like the Elixirs). Sweet! I walked into this section of the screen that wasn't obvious it was a transition point and suddenly found myself atop an amazing vista where my party members had a nice conversation? Very nice!
That's just me, though. In general, I don't like these "wild loot" items as an adult, because they tend to turn exploration and immersion into a "checklist". Completing a checklist in terms of exploration just doesn't feel "satisfying" to me as someone who likes exploring game worlds.
And, honestly, that's to say nothing of inflating your economy pretty badly in the game either by adding 50+ instances of "Got Potion!" to the game world. But, that's a topic for another time.