They did add a bunch of achievements for each gamr, collectables and in game purchases along with a plattform to trade those. But it is not on the nose, and mostly cosmetic stuff like skins as far as I can tell. All of that is offset by Steams drive to get more and more games playable under Linux so.
It’s been in existence for 20 years now, so I‘m rather amazed by how little it has changed, while obviously the background work (scaling, security) has always kept up.
I love it, really do! And as I said, the trading of in game stuff, that doesn't have game impact most of the time, is more like a fun add-on for people who like it. Steam is a great service, something that represents the internet we could have had in a different time-line.
>> It's not obligatory to have achievements unlike on the PlayStation
While it is indeed mandatory for your game to have achievements on Playstation, the TRCs don't specify anything about the quanity nor quality of those achivements. If you want you can launch the game with a single achievement for starting the game and it would still be approved.