Charge a dead beat's rate and you will get just that.... deadbeats.
My weekdays almost always go vacant because the going weekday rate in Southern California is about 1/2 to 1/3 of the weekend market rate. Not worth my time. Not worth the risk.
With regard to accepting payments outside of Airbnb, I would never do that because
1) if you don't charge a transient occupancy tax (as Airbnb does automatically) and you happen to book someone for as little as a one night stay, and they refuse to leave (AKA a "squatter") you must take them to court to get them out. Simply by virtue of guests paying a transient occupancy tax, the are legally transient occupants -- not tenants, and therefore the sheriff will haul them out of there ASAP.
2) Airbnb adds a layer of insurance (in addition to the homeowner's insurance with Airbnb rider, which you should have).