Conversion of Leftover RP

If you've bought RP and got some skins or chests, I'm sure you've been a situation where you have left over RP that is completely useless unless you add more RP. Maybe this is Riot's method of making us buy more RP to compensate for the leftover RP, but I'm suggesting an option where you can convert RP into IP or into Blue/Orange essence. Leftover RP=Useless. Who's with me?