Level 6 & 7 Masteries?

I'm confused, l get that getting S- and above grants you your characters tokens but in terms of having all their skins and obviously the character why would you get their shard? Furthermore why is it only BLUE essence that's being crafted for the characters. I've gotten a couple S's and literally find it really rare now to even get a chest, I have ironically gotten keys but I can't even use them since I can't get chest. The only way I see around this problem is to actually use money to get chests and hope for a champion to scrap and fodder for BLUE essence, it seems kind of unfair to be honest.