The thruth is that this was one of the the greatest marketing ploys in boxing history. The fight was a tune-up fight. Though if you look closer there's so much to it. Basically Mayweather killed 4 birds with one stone.
1. Mayweather evens the score with Pacquiao.
-Pacquiao was coming off the De La Hoya fight. De La Hoya gave Mayweather alot of problems and Pacquiao made quick work of him. Mayweather needed to get even by dominating the guy who many people believe beat Pacquiao. Enter Juan Manuel Marquez.
2. Maywether needed a tune-up
-Mayweather was coming off a two year layoff and needed a winnable fight to shake off ring rust. TBH I really don't think Marquez thought he could beat Mayweather and just wanted the fight for a payday.
3. Mayweather needed to move up the ranks quickly
-As the former p4p champion (according to RING) Mayweather needed to climb up the rankings quickly to show the world he was still the man. It just so happened that the guy who gave the current p4p king all he could hadle was ranked number 2. Beating the number 2 + Being the former number #1 and never being defeated for that spot automatically put Mayweather at #2.
4. Mayweather needed to prove his drawing power
-This is the most surprising of all. With slow ticket sales and people saying nobody wanted to see this fight, Mayweather managed to make his way into over 1 million homes! Thus proving he was still an attraction and still had power at the negotiation table
All in all Marquez was the perfect opponent for his comeback fight