I feel like upgrading masteries on champs is not worth the price
3000+ for upgrading to mastery 7. Yezz I got 40,000 spare (after buying every single chroma, emote and gamer pic available) and even I don't feel it is worth the price. The only reason I even upgraded to mastery 7 was because I sort my champs by mastery to figure out what I want to play in normals...
The only reason I would upgrade a champion wastery in the future would be for that purpose only or if I end up with 100k+ Be and have nothing better to do with it