There is such a diversity of properties on Airbnb that one size fits all for cancellation policy is never going to work. Why not let hosts choose the % of cancellation fee and timing of penalty to suit their particular context?
Rationale: The policy is now global of having 100% refund to guests for hosts with Flex or Moderate cancellation policy - ie there used to be a disincentive of paying Airbnb service fee, but that is now refunded to guest. The only option to provide disincentive is to have a Strict cancellation policy that means that guests pay at least 50% on cancellation - a harsh penalty, and a glaring gap between this and other policies. Home lettings are not hotels! Some hosts will be affected much more than others with this ease of cancellation, especially remote, seasonal locations.