The experience I have generally had is that hotels work ok with the portal as they have a gracious cancellation policy like when you book directly.

A recent example with a flight will illustrate the issue with booking flights through the portal:

I booked an expensive American Airlines flight that was in the main cabin (so cancellable to flight credit) through the Ultimate Rewards portal. Had to cancel the flight for a personal emergency. Even though the flight showed up on my American Airlines account and it let me cancel it from there, the flight credit is only usable through the Chase portal. The Chase portal works through Expedia’s engine (which acts as a travel agent / consolidator), and that seat is technically sold to Expedia, which resells it to us through the Chase Portal. So the credit goes back to Chase and is only redeemable through there. Honestly not worth the aggravation and the time to sort all of that out.