After browsing the internet in the past few days, Genshin UGC is not for the casual Genshin players. ...and that's a GOOD THING. It's gonna get the audience out of Genshin anyway.
All I see are complaints about it not getting primos, adding up more storage, comparing it to TCG, mocking people that are excited about it, judging the game mode entirely on cosmetics, and other reasons that are just stupid. To clarify:
>It's not giving out any primos (except on current web event and the Manekin/Manekina's 3 Acquaint Fate Rewards for ascending it)
>It's gonna add more storage BUT not a lot. Majority of it already uses Genshin's assets, and you only have to download additional files when you want to play a certain game.
>You cannot compare TCG to UGC. TCG might be a separate game mode, but it's a permanent one within Genshin itself. UGC is marketing itself as Miliastra Wonderland and is running outside Genshin and is only using its assets.
>To mock on other people's excitement is a jobless behavior.
>Cosmetics is not the core gameplay of UGC. One might say that it's pointless for the theme banners to exist... and they are right. It's completely optional to dump money on UGC as it's not important to progress on it.
People are forgetting that League and the MOBA genre came to be because a UGC map in Warcraft boomed in popularity. I spent hours in computer shops to play DotA with friends during my high school days. I didn't even touch Warcraft in the slightest. UGC will be beneficial to the Genshin brand in more ways that you can imagine. Genshin's elemental system is already great. Imagine someone in the UGC revolutionizes that with a unique idea.

I'm already seeing the possibility that the UGC will have more active players than Genshin itself in the future, and the majority of these players will not even touch Genshin.