Moved to Game Mechanics Design. Conceptual game-design questions like these go in the Maker General area (either Game Dev General Discussion, or Game Mechanics Design - or, if the question is about your game specifically and wouldn't be applicable to most games, then in Ideas & Protoypes).
If you want the discussion to focus only on the specifics of your game, you can Report this post and ask for a move to Ideas & Prototypes.
It's hard to make a Yes-or-No call about this! My thoughts on the matter are pretty complex.
In general, if such a skill were to only show me an enemy's HP, MP, TP, and Stats, I probably wouldn't spend a turn to use that skill. Against regular enemies you don't need it, and against bosses the Stats are the main useful information (unless you plan for your bosses to regularly run low/out of MP) - and while the Stats can inform what kind of strategy I should use against that boss (are his physical or magical attacks going to be more powerful? and which type of attack would be more powerful against him?), I think that if you've done a good job designing your battle system and UI in a clear and informative way, then the player should be able to deduct this on their own after seeing several actions and their results.
A lot of games include extra information in addition to what you've listed. Among information I've seen in Scan skills are the boss' elemental weaknesses/resistances, what States are easy/hard/impossible to apply to the enemy, the boss' entire move set, what the enemy could possibly Drop, and written descriptions of the enemy (which might give a hint about their moves or tactics). Whether this kind of information is good or bad to give to the player is really based on what kind of combat dynamic you're going for (is it more about surprise and learning, or is it more about using information to make interesting and strategic decisions?).
I very much like
@Oddball's suggestion of a Scan forecasting the enemy's intention for the next move, although to implement this in RPG Maker you'd need to create (or find) a plugin that determined the enemy's intention a turn in advance, which could be tricky.
Many games give you a Monster Book to hold the Scan information you've gotten from enemies, and some games even reward you for getting to a certain number of entries in it, which can make the Scan action more appealing for completionists.
Finally, I just want to point out the option of revealing any or all of this information to the player
without forcing them to spend a turn nor sit through the Scan animation and the stats screen that inevitably comes up about the enemy afterwards. In one of the games I'm building (where my emphasis is on strategic and creative decision-making), any time you're hovering a battler, you automatically get to see their HP/Max HP, MP/Max MP, "ATB" Gauge, Base Stats, Current Stats (affected by States etc.), current States, and exact Element Rates for each element - no need to Scan them first. This doesn't make things too easy nor too boring - it challenges the player to use this information and find combinations of skills that will work out well against enemies with these particular stats and weaknesses. Since my game throws enemies together in all kinds of different combinations, that challenge never really gets stale, either.
