For a lot of people, "tourist trap" doesn't register as a thing - those are just the things you _do_ when you go to whatever place you're going to.
If Airbnb becomes the safe, convenient, well-marketed way to discover reputable but not stereotypical local experiences in a marketplace that takes your credit card, they could do well IMO.
AirBNB aren't the first people to try this, but they're pretty well placed brand-wise to sell the 'real local experience curated by ordinary local people' image. And yes, in practice it'll leverage that to sell standard tourist activities and some customers will be delighted, just like they use AirBNB to find ideally situated self-catering holiday apartments run as businesses rather than airbeds in suburban spare rooms
That said, I don't have any real insight into the tourism market and won't be shocked if this works out well for Airbnb. I personally try to avoid crowded tourist spots like the plague and this could just be my bias talking.