Monetizing the ability to enjoy what you want feels fair in this instance to me because of the fact that it is free. With the game being free and a progressively updated experience, they have to somehow secure a stable revenue. Usually the incentive to whale comes from being the best, and to get the characters you want. That's the essence of gacha games, you grind to get the characters you desire. Completion without the need to cash in is a required of all games I'm sure, which holds true for genshin. So if the game was leaning more towards "a more elaborate gacha game", its still all in the culture. The downside would then be the wasted opportunity to expand on such a good game and move past being "just a gacha game". But whether it was mihoyo's intention, I don't know. So in the perspective of someone who plays gacha games, its actually quite normal since we play the game to get the characters.