Listings which are on the "host-only fee" structure have this message right beneath the booking form:
The "piggy bank" icon pretends there is a saving here.
Also the booking form displays this line: Service fee $0
IMHO this all is misleading to guests, as they still pay a Guest Service Fee, but it is included in the renting price.
Guest may also think listings on the "split-fee" structure (charging them a Guest Service Fee) are more expensive.
But when it comes to "long term stays" (LTS) such listings are even cheaper, as the Guest Service fee for LTS is significant lower (-4%) then for "short term stays". The 'host-only fee" structure makes no difference on this, as it is same percentage.
About fees:
https://www.airbnb.com/help/article/1857/what-are-airbnb-service-fees