So other than forcing people to waste BE, what is the reason for mastery 6 and 7 costing BE?

It's a sink for people that have a lot of BE.

I honestly want more BE sinks. i've changed my name twice. i still have over 100k. I have nothing to ever use it on and im actually trying to get more master 6 champs just to dump this stuff.

Forcing people to waste BE.

I like to think it increases the size of your E-penis. =/= Therefore worth.

That's it. No reason other than to waste BE.

But the reason to waste BE is it lowers the value of BE. So even though your getting roughly the same as IP (everyone's favorite point in an argument), your actually getting less because the value of BE is less than IP.