I have to agree with @Super47
I can confirm from my personal experience that using IB or not does affect bookings and significantly in a market as saturated as London. I started off not using IB with no problems at all. Then suddenly Airbnb really started to push IB, my listings dropped so far down the search results that my bookings pretty much stopped completely. Also, who knows how many guests were inadvertently searching with the IB only box ticked and therefore never seeing my listing at all?
Reluctantly, I switched IB back on again and hey presto, the bookings flooded in. The thing is, the vast majority of my bookings are not IB but via requests, partly because I have all the extra requirements ticked for IB, but largely because most of my guests prefer to have some correspondence first. However, I needed IB for those guests to even see my listings.
I am talking about a couple of years ago, so who knows if things have changed and I would now get the same number of bookings with IB switched off, but it's not something I want to experiment with right now after such a dire year.
Also, I haven't found IB bookings to be more problematic than request bookings. There are good and bad guests who use either method. The advantage is that you do have three penalty free cancellations so it's much easier to cancel an IB guest if red flags start popping up after the booking is made.