I discovered the change recently as well. Here is what Airbnb's Customer Experience team had to say about it:
"The reason you are seeing the prices in cents is because of our new Precision Pricing that rolled out in June. This new pricing helps us to achieve greater accuracy in how we price, charge, and communicate amounts throughout the product, resulting in less customer confusion and CX contact rate. Guests will be charged in the decimal level accuracy dictated by their currency’s standard and hosts will similarly be paid out in the correct level of precision based of their payout currency. I hope this helps!"