One consideration for using MHV: eligible for credit card cancellation insurance
AMEX (at least in Canada) 'sees' a booking via the MHV portal as eligible for cancellation etc coverage; AirBnB VRBO etc are not covered. This vendor relationship via Marriott was new for them so they ran it as a dummy booking to see what coding showed up and confirmed we had coverage. On the statement, the payment shows up as made to Home Villa by Marriott...
This is a key feature for us esp in light of the nonrefundable nature of some of the bookings we were about to make; and IMO worth the small premium vs booking with the AirBnB etc. side note: I find the ticky tack additional fees from AirBnB etc to be frustratingly opaque compared to the MHV dashboard.