Why would I want to boost map boss difficulty?..

Aside of uber fragments from citadels it seems pointless to me.
I guess you can get that +15% quant, but other than that it's pretty meh.
While changes to bosses hp and damage are pretty damn noticeable and don't fit overall map difficulty.

Basically what I'm saying is that map boss passive tree should be more rewarding OR less punishing. Otherwise I will only use it when I run a bunch of citadels back to back with the "bossing" skillset and mindset.