Some large chains will only give you rewards points or honor your status if you book directly.
My wife and I just spent several days finding and booking hotels for a 2 week trip with several stops. We searched on aggregators (Booking’s “king size bed” filter was particularly useful) but always defaulted to booking directly with the hotel. Oddly enough, one hotel had no means of booking directly; they only supported booking through an aggregator. One other hotel was offering the same price via Chase Travel, so I took the extra bonus Chase points.