Wishing is the gacha element of Genshin Impact, allowing you to randomly receive weapons and characters of varying rarity in exchange for premium currency. Players are able to do one Wish at a time, or do 10 Wishes at once.
The only bonus associated with pulling 10 Wishes at a time is that it’s faster. The gacha banners say, “Every 10 wishes is guaranteed to include at least one 4-star or higher item,” but this does count for single pulls as well. The 10 Wishes required to pull a 4-star item refreshes every time you get one, so even if you pull a 4-star on the first or second Wish, the 4-star Wish count will still reset.
That being said, if you’re aiming for a specific character and you have limited funds, you’re better off pulling one by one until you (hopefully) get them, rather than wasting your Wishes pulling 10 at a time.