The situation with ABBs in Japan needing licences and the fact that it is really hard to actually get a license (not impossible but very close) has been a widely known concern. And based on my personal experience with ABB as a host, I would not expect ABB to pay guests for a hotel because a booking fell through last minute - ABB could however help to find an alternate listing that is available, and how much additional credit ABB provides would be under their own discretion so the guest may have to pay in addition if the price difference is significant.
ABB has it's own pros and cons if we compare to hotels and it is my opinion that in the end, it is really up to the individual traveller to consider the pros, cons, and risks before deciding what/where to book.