I know this is a touchy subject. I just have a simple thought to add. Disclaimer: I use IB and it has been great.
I was speaking with some guests as they were leaving. They were saying that it was so difficult trying to book an airbnb because most hosts never write back - or do so a day or two later. I’m sure that most of us on this forum are more professional than this. But it has been my experience, also, and it is extremely frustrating as the consumer. When a person has time to book the details of their trip, they want to get that job done. They don’t want to attempt to book one place, then have to wait three days for a host to respond or not, then have to start the process over again.
This guest didn’t really understand that I had instant book, but he appreciated very much that he was able to book immediately.
So perhaps the whole IB thing, in part, is to make it easier for the consumer since so many hosts are not professional.