To be clear I still enjoy the actual games or I wouldn't play them, but your resources are often more limited in these and you can't get everything that comes out without spending, so part of that enjoyment factor comes from which units you run/invest in where this isn't even usually a topic that comes up for non-gacha games.
I think you'd have a rough time with HSR if you never pulled for characters because the basic set aren't really able to keep up in the current game era so it's a critical component which is baked into the game and how it plays.
These types of games aren't really that deep usually, they have a story and things but they can never end it, so it's more about the content along the way and the events/new chapters and things that get added over time. For HSR we are between patches and the next major update so there isn't really anything else to discuss at this time.
I wouldn't play the games simply for waifu collection, I've dropped games where I didn't click with the underlying game or systems.
This is of course a general gacha thread and if discussing things like pulls or character priorities for HSR bothers people, we could just make an HSR thread for the people that play it.
Infinity Nikki - how does the gacha work? do you need to summon or is it just cosmetics? from what I can tell it looks like more outfit based than anything but I've not played it so don't want to assert that without knowing.