To me, there's definitely some value was added by the service by doing some screening. I didn't ever pick somebody who had no reviews. But that's valuable for the first time, worth much less afterwards. We've used 6 or 7 different "sitters" because the first, first 2, first 3, etc. were booked or not available.
Our primary sitter went private. He's got magnetic signs advertising dog sitting on his truck. He charges the same rate as when we booked through DogVacay but we pay him in cash, not via credit card on the website. I text him to see if he's available and so far he has been. I think he's less busy than he was using the website but the flip side is that he's not paying a fee so I bet he nets out better or the same. Plus he's dealing primarily with repeat customers - dogs that he's familiar with, dogs that are familiar with him.
The matching has some value. It's too bad there isn't a fair way that he could have us as a repeat customer - which is due to him being somebody we think is trustworthy - but pay less to Rover. Something like 25% (or whatever they charge) for a first-time stay, 10% for repeats.