On one hand we have the undefeated 49-0 out of retirement, most successful boxer of all time (soon to be 50-0 ). Somethin' like 5 belt classes, 12 time defending champ... Nutty
On the other hand, we have a champion of two belt classes of MMA... but he's boxing for his first time ever, and actually lost recently to Diaz in their first match of MMA.
Here's an analogy related to Connor trying to fight in boxing from mma:
This fight is like telling Sidney Crosby to play goalie for the Pens. Sure, it's still Hockey... but do you honestly think a center with a few months practice in net is going to be able to compete with an actual goalie? Who's lifetime training, experience and career is to be a goalie?
Mayweather is going to crush Connor, and that's that.