Gem entire army and spells at once

With the new army overview window, there should be an option to gem all of your barracks and both spell factories to completely finish training your army. There could be a discount for using this option rather than gemming each barrakcs or factory individually, or it could just be for convenience and save a few precious seconds. I don't think this would be hard to implement and it would probably entice more gem spending, making it convenient for players and supercell alike.
Alrighty, that's all

I believe that if it's to add new buttons to fill up the space, then they really should have a good purpose and not just to make us save few seconds while filling up the space with buttons only used in rare moments.