It's somewhat fashionable for well-off people/families to have a vacation home somewhere vacation-y. Before Airbnb, most of those homes just sat vacant for most of the year[0]. Clearly, that's not a great use of that land. Often these sorts of properties would be in pretty desirable locations, and doing it this way would deprive most people the use of that space.
Certainly there are still some people who are wealthy enough to keep their vacation homes vacant most of the time (and prefer it that way, since doing short-term rentals tends to involve quite a bit of wear-and-tear on a house and its furnishings). But many list on Airbnb now. I consider this a net positive for society.
Of course, Airbnb isn't all roses. In many places, investors buy up housing stock that would otherwise be used for long-term rentals, and deprive locals of much-needed stable housing. My guess would be that this is even -- unfortunately -- the primary use of Airbnb these days (I doubt they are primarily people renting out a room in their already-occupied house anymore). So this does suck.
On the renter side, I've found a lot of great places to stay through Airbnb over the years, experiences hotels just can't provide, and often prices hotels can't match. Should I just not be allowed to have these sorts of experiences? (It's totally fair if the answer to that is "yes", as much as it'd be disappointing.)
Can we find some sort of balance so that we can curb most of the negatives that come with real-estate investing, but keep most of the positives?
[0] Yes, vacation rental companies existed before Airbnb, but Airbnb completely changed this space.