I travel a lot for work (100+ nights per year).
Sometimes I stay for 2+ nights, often it's just a 1-night stop over.
For 2+ nights, I almost always go with an AirBnB - more space to cook/work/think etc.
For 1 night though, AirBnBs are too much hassle. I don't want to have to choose a great location from a long list which includes some terrible options. I just want a clean bed, bathroom and decent wifi in a good location. HotelTonight gets me that in under 30s.
I'm not sure how AirBnB locations can/will be built into HotelTonight - after all HotelTonight is all about ease of use, low friction and flexibility. The very things AirBnBs are bad at (coordinating check in times etc).