I wish Genshin had more official illustrated content, especially in game. Because I'm looking at hsr light cones, and then genshin's TCG cards and I'm in LOVE with art styles and featured content. Especially with the light cones, they are so beautiful and I love when illustrations tell us a little story (like with 'Warmth shortens cold nights' and 'Geniuses' Repose', those are one of my favourites).
(art credit to hoyoverse)
I think they add a lot to the way we perceive characters due to the fact that we see more of them more often. We also learn some personal stuff about them which is always good for a game which tries to put quite a lot of focus on characters and their relationships, especially lately (I think this is true for both genshin and hsr)
I also really like that a lot of hsr illustrations are just slice-of-life of featured characters and I desperately wish for more slice-of-life content with playable characters in genshin. Big, nice illustrations they post for occasions are great, but pretty rare. I don't know, I guess I just want to see more characters interacting casually (and also more illustrations)
Sure there is some kinda-slice-of-life illustrations in Genius Invokation, but not much (ex. 'I haven't lost yet' and 'Quick knit'). But I wish we had more because the art style is, once again, gorgeous and I really want to see more characters interacting, even if it's just some additional content which doesn't add much to the story. Idk, I just feel sad that we see some characters only once or twice a year, they deserve more appearances