What sort of insurance? My wife booked an apartment in London several months ago. Got there in November and it wasn't anywhere near what was shown on the site - same location, but size, amenities, etc were all not as advertised.
He is talking about the insurance AirBnb offers to host in case a guest messes up the place.
A well publicized incident happened where someone trashed a person's place. The insurance AirBnb offers makes you try to use your existing policy first.