While I understand that point being discussed here regarding taxation etc, generating revenue off the both involved parties is in fact kind of how Airbnb charges for their services, no? They provide venues of communication/escalation/payment etc. in a safe manner (or it should be at least safe) in exchange for the service fee.
Good example: we rented an apartment in the EU a couple of years ago, when we moved from the DR to EU. The same unit was offered privately, directly from the landlord and via Airbnb. Difference was that while the rent itself was a bit cheaper renting privately, we would have had to pay deposits and such, while with Airbnb that was not necessary as they take responsibility of things should anything go wrong, so we went with the Airbnb route, it was more convenient for the landlord and us, as while Airbnb charged us both something for their service, we both got peace of mind and we paid no deposits. Please bear in mind, the deposits were not something you would pay in the DR, but for a unit for 4 people in the EU, so thousands in EUR. With another unit, we even had some trouble with the landlord (no fault of ours) and the moment he wanted us out from there, Airbnb was looking for alternatives for us and even paid for the first few nights for us, just so they could calm the situation and we would not have to deal with the problem landlord.