I agree - chornological order makes the most sense.
If a host rennovates their house, they would need to delete and re-create their listing, because whatever poor ratings they got in the past would persist for eternity.
If Airbnb doesn't change this, I can see an increase in hosts creating extra accounts for their listings if they get bad reviews.
This also gives a tremendous amount more power to guests. I've been blackmailed before: either lower the price, or we will give you a bad rating. Airbnb had my back on that one, and decided not to show that rating, which I'm very grateful for, but if the guest had managed to get away with this, this new feature would have displayed their negative review forever.
In short, guests are more empowered to blackmail hosts for lower prices at the end of their stay as a result of this feature.