No, you're not missing anything here. In men's pro pool, these are the times we live in.
When there was a proper tour with a published list of player members under contract, a promoter could approach a potential sponsor and promise the participation of those player members. This made the pro pool product an easier sell to venue sponsors, those wanting banner or booth space at the event, and fans keen on following their favorites on the tournament trail.
The Bonus Ball guys (please, no bashing of them in this thread) have shown they understand this and fans like me and you appreciate knowing, more or less, which players will play on what night well in advance. They've also shown that locking up the players well in advance of an event is not something easily, or inexpensively, accomplished.
.... so, JohnnyT, you and I live in a pro pool world in which field size and quality are something we, all too often, find out at the last minute, because so many pros are deciding at the last moment whether or not to participate.
The Ultimate 10-ball event is still a month and a half away, so there's nothing shocking here, but any elite players who play Bonus Ball while the Ultimate 10-ball is in progress will be making a statement, and, at least in my view, they will be making the wrong statement.
Stay tuned.