Let us buy XP boosts with BE.

Right now I am just collecting champion shards and BE that I can't really use besides upgrading champion mastery lvls, which I really don't feel like doing. So I was thinking, why not allow us to buy XP boosts for BE. Make them more expensive than a lvl-up (every 3-4 lvl's you can afford the lowest one or something similar).

This way players are allowed to use their useless BE and feel like playing the game more. It can also be used as rewards fro various things, like honour goals, Hex tech boxes, etc.