MVP would put on fun fights if matched up properly. He'd never come close to a UFC championship though unless they give him perfect matchups, which wouldn't really happen in the current state of the WW division where there is a lot of high level grapplers. He's also 34 years old and doesn't have many years of prime left.
Leon Edwards on the other hand is just 29 years old and is one of the best WW's on the planet. Probably presents the toughest threat to Usman right now (even though I believe Usman wins), and will likely be a top contender for the next several years. It would be pretty tough for the UFC to justify a trade like that.