My suggestion is to have a button in your den where you can level up you lions that are able to be leveled up to reduce time "wastement" of jut going through tons of lions having to level them up individually. If you have a large pride and you don't go through your lionesses and level them up everyday you know what it is like (I am one of them)
It is just to help people who are lazy, just like me or people who want to save time. Or if you do not want to spend 2 GB for reasons such as; you are saving, you don't want to spend it, etc.

Edit: I just realized that there is an oasis item but this is also a button where you can level up for free. Since leveling is basically an easy chore and you don't have to pay for a task that is in 2 or more clicks.