Would you be against or for rewarding good performance in parties?

[Vidu]

this would kill the game so fast lol

Can you - or anyone who doesnt like the idea - explain why though?
I mean, seriously the idea is:
"Oh, you did very well in this dungeon - here have a little extra bonus to reward your for that!"
Oh, someone else wants that reward too? Sure, no problem, they just need to do well too!*

Leaving the fact asside that its very difficult, even outright impossible to implement such a thing, I dont get why some are even against the plain idea of rewarding someone for the (extra) effort and for actually performing well - the only people who'd get upset/left out here would be those who are clearly underperforming and basically getting carried through dungeons atm (yes, even a casual player can be underperforming and should be expected to do well - not savage-good, but well)

*well = a meat, that a normal player whos paying attention, knowing his rotation etc. can achieve without having to be close to savage-performance