For a single reservation the payout is the accommodation fare plus the cleaning fee, less the platform's host service fee and any refunds — so recording the deposit as revenue understates the top line by exactly the fee you were charged.
Both halves matter and both are lost by the shortcut. The revenue understatement is obvious once stated. The quieter loss is the fee: an expense that was never recorded cannot be deducted, so a host who books only net deposits pays for the platform twice — once in commission and again in tax on income that was never received. Refunds behave the same way, disappearing into a smaller deposit rather than appearing as the reversal they are. This is the same decomposition problem that runs through every platform-mediated business on this site — it is what our ecommerce pages and the Stripe reconciliation work are built on. What is specific here is that the units being pooled are stays at physical properties, which makes the second question unavoidable.