The ONLY time I've paid a host outside of AirBnB was when he set up a driver for us to get from the airport to the rental at KBP as we were arriving after 36 hours of travel and knew that there would be a significant language barrier trying to get a taxi. Obviously outside of the scope of AirBnB.

In my opinion, linens are specific to the room rental, and should be paid through the app.

By the way, two cities we can't wait to visit again are Warsaw and Kyiv. We loved both of them as they weren't full of "Instagrammer tourists" and had a lot of offbeat areas to explore.