I hated steam a long time ago when it was so buggy, buggy offline-lan play and it didn't have a lot of games. Aside from the DRM it added nothing.
But now, you can use it to find game-buddies, you can read user-reviews on a game before you buy it (very helpful to filter out those buggy crap games), cards (can be addictive), ingame messenger that acts pretty much like the old XFire, etc.
It's good now imo. And yes the Christmas sales for example have discounts ranging from somewhere between 25-90%. Just lovely.
Steam Achievements by the way would be weird for RPG Maker Ace. "Place a 100 events" or "Crash the game 3x in a row"

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