Personally I think it's a mistake for Billy suddenly to try and transition to Challenger level in a search for ranking points, especially as you still have to qualify to get them. If it functions as it should, the transition tour should act like the second tier tours do in golf; the 15 players or so that top the rankings get automatic promotion to the main tour the following year. The transition tour isn't scheduled to act exactly like that, but with the qualifying WCs if you are near the top of the transition tour, and the fact that it will draw more attention to yourself by being at the top of the transition tour rather than somewhere in the 300-700s as is now the case, I would think that for someone like Billy the first target would be to make sure he is as near to the top of the impending transition tour points as he could be. Going off to play quite likely relatively fruitlessly in Challenger tournaments might in fact make it harder for him to do this, and thus harder for him to 'transition' rather than easier.
I get the point your making Michael D. But without the change in how the tour is going to work going forward. Surely Billy should be pushing himself anyway to try Challenger Qualies?
I think that it will be some time before any of the players really work out what the best strategy is going to be. I spoke to a couple of others as well and many of us on here are more informed of the new structure than the players themselves. My gut feeling is that it won't make much difference at all. Players will enter at the level they feel appropriate and that has/will always be the case.
As for Billy, I don't think testing himself at challenger qualifier level from time to time does him any harm. In many ways, if he could get a couple of wins and perhaps make it through to an MD, it would do his self belief the world of good.