I have been traveling for the last 2 decades with a disabled SO and I can tell you, it will take the same "event" (i.e. lawsuit on accessiblity access) as with Uber before AirBnb will make significant changes to ensure that hosts that ticked "wheelchair accessible" option means that their property is INDEED wheelchair accessible.
I remember back in late 90's - ealy 2000's, major travel sites (Travelocity, Expedia, etc.) did not even have an option to search for accessible hotel. Today, it's right there.
It is very frustating to arrive at the host property, thousands of miles away from your home and after long hours of flight, and you find out you cannot even get into the building (stairs, etc.) or the bathroom (door not wide enough, etc.).
The best recommendation I can give today is to contact the host that ticked "wheelchair accessible" option to CONFIRM that they HAVE the following:
1). NO stairs into the building or your room
2). The WIDTH of the doors (front, bathroom and your room) can accomodate xx inches/cm (based on your wheelchair width)
3). The bathroom can accomodate your ENTIRE wheelchair (width and length) that you can close the bathroom door