All respect to McGregor as a fighter, bit there's 0 chance he even approaches Mayweather skill as a boxer, no matter how good he thinks he is with his fists. Mayweather is probably one of the best technical boxers on the history if the sport, and some of best boxers in the world couldn't touch him. MacGregor has never even trained boxing full time sonce he is an MMA fighter, nor had any pro boxing fights, nor any amateur boxing fights that I am aware of.
It's a spectacle for sure, but the outcome is very obvious. MacGregor is just doing this for the payday. And who can blame him? 75 million is his rumoured pay, Mayweather 100 million. He won't suffer any damage to his MMA reputation since the fight is boxing only. Aside from the fact that he will lose, it's a slam dunk win for MacGregor.