In the game Genshin Impact, you want to level up your characters so that they can be more powerful and deal more damage, but after you collect stronger characters (like 5 star characters), you will want to use those newly acquired characters instead. The problem is, there is a limited amount of character exp in the game and it is hard to level up your new characters because you won’t have enough character exp. If the creators of genshin impact, miHoYo, released in an upcoming update a feature where you could reset the level of a chosen character to 1 and regain 100% of your materials invested (character exp), then it would be a lot easier to level up your desired characters. Example: Amber is at level 25, you have a better pyro character that you want to use now, BUT you don’t have a lot of materials. Example 2: Lisa is level 25, you get Keqing, you don’t have a lot of materials to level her up. 
This new feature would help a lot of Genshin Impact players and could help miHoYo advertise Genshin Impact. MiHoYo obviously spends a lot of time invested in creating new events, characters, battle passes, etc. If they put in this new feature, it would be really amazing. What’s the point in wishing for a 5 star character when you won’t have enough character exp to upgrade their level?