@Sarah1866 I'm very on-grid, so I don't have any relevant experience to share here. But what I don't understand is why a genuinely off-grid owner would choose a completely web-dependent platform for their listing.
Correspondence between the host and guests within the online platform is the primary evidence available to customer service if either party has a problem or dispute. So while internet access isn't a required amenity, it's pretty essential to following the procedures Airbnb demands for issues such as guest refunds or host damage claims.
There is definitely demand for some truly off-grid, remote listings, especially in these times of social distancing, but perhaps Airbnb is not the ideal tool to serve their needs.