The top prize is $50k, which is $10k a player before they pay out any coaches, analysts, and org cuts. It could be as low as like $5k per player which is like 2 weeks salary for them. I don't think they care THAT much about winning.
My guess is that because of the upcoming chamber patch, they wanted to test out some cryo jett comps and ascent was a map cryo had played jett on during the chamber meta so it serves as a decent gauge
Its better to practice a map and get better than just making a map be a perma-ban especially since its the off-season and the tournament is for practice instead of focused on just winning plus zander said their ascent is good in practice, imo they just need to work on it for matches.