It seems that you don't play Genshin impact game. You can't buy ascension materials with money. You pay for stronger characters with more versatile playstyles,

It seems that you don't play Genshin impact game. You can't buy ascension materials with money. You pay for stronger characters with more versatile playstyles, but it won't make the game less grindy. You still have to fight for materials by yourself. Also as other said, different f2p games work differently. In Genshin, you can easily complete the main request with free characters. Most people (like me), just pay to pull for particular characters they love. (Just check Hu Tao's character demo from their official yt account and you may get a glimpse how the characters (regardless of strength) are attracting themselves.))