Looked into Points Boost with airfare a bit, and for now it could be quite a lot worse.

Somewhat lazy survey of carriers suggest it's only good for flights on UA and AC metal in premium or "premium" cabins (UA domestic Economy Plus sometimes counts) at 1.75c for PE and 2c for F/J. I believe it is a blanket discount applied to all flights, with the somewhat common exception of non-public fares, either because the prevailing fare uses NDC dynamic pricing or because Chase has a private fare, although in the latter case you are getting better than the nominal rate versus the price from United to compensate.

I assume it's basically any premium cabin fare on those airlines where the TA is collecting full commission, so ironically this is actually feeling somewhat akin to Amex IAP.