My St. Lucia property is also listed on Expedia and Booking.com. They each charge me 15% commission, and I have to incur the credit processing fee, which is 3.5-4.0%. Additionally, I have to deal with the headache of non-valid credit cards. Both OTAs (online travel agencies) allow a guest 24 hours to provide a valid form of payment. During this time your calendar is blocked. Expedia also has an option where they collect the money for you, and that fee is 20%. Their preferred payout method is via EVC (electronic virtual card) which is processed like a credit card (so that's another fee to deduct out of your earnings). Otherwise, you can invoice them, and it takes 30 days to receive payment (direct deposit to my bank account).
Of course, all of these fees are still passed onto the guest. So, Airbnb isn't charging any amount that isn't the current norm for OTAs. Personally, I prefer paying Airbnb their 3%, and knowing that I will have money deposited in my account the day after the guest arrives. What I like about processing the payments myself is that I have the credit card number or cash for the refundable damages deposit. For cash deposit, I usually charge no more than $300USD for the guestrooms, and $500USD for the apartment. Although this amount would barely scratch the surface for repairs or replacement, it's a great behavior modifier. Compared to guests where I've not taken a deposit, the aforementioned guests take more precautions with the amenities and furnishings.