Is there any benefit besides loot to playing Mann Up mode in MvM?

Recently gotten into playing MvM, it is quite fun and I haven't really encountered the spools of toxicity Ive been warned about, and just play Boot Camp. But is there any reason to play Mann Up mode besides gambling? I don't want to pay to play and get loot I don't want or need. Do you get generally more competent teammates? And there is like a way to buy one ticket and like play infinitely if you leave at the end of the match or something?