Champion mastery

I think it's really stupid that playing other game-modes than normal does NOT give you any champion mastery. I can understand co-op and such, although they should consider getting mastery for that too (maybe a smaller amount) It's not like you don't learn to play a champion through ARAM or Treeline, if anything, you may learn it even more in ARAM, as in some cases you are forced to play something you're not that used to playing. It really pushes you outside of your own comfort-zone, and you should be rewarded equally, if not more, and I fail to see the logic as to WHY we do not get mastery points in these modes, other than greed.