Airbnb does not tend to collect these taxes for the fun of it, and they dont do it free of charge.
A such I would guess that the agreement to do so has surely come from discussions from the authorities, who must surely believe it is in their interests and easier for them to implement that what you describe is the current procedure.....I am only guessing..you know more about your area than I do.
Maybe you should see if there is a local Airbnb host group that you could join and collectively ask for clarification as to how this new system will work.
Maybe also contact your current authority that you pay to....and ask if they have joined this new system of payment collection.
Airbnb has your property address and as such zip/post code so it may well be automated to send the authority the owener/property address and tax collection.
Of course it would help if you were informed if that is the case