>> - Popularized the idea of sharing a space when the host is there

this was not a popular option, and I don't believe was ever intended to be. It also opened the door for VRBO to gain traction explicitly marketing NOT sharing accommodation. The "rent out your spare bedroom" has never been a major component; it was a fake-out to counter the regulatory & licensing complaints they were facing.

In addition to the sibling comment saying that it was a major marketing focus, it was also an internal culture focus for some time - the archetypal host as discussed internally was something like a 50+ couple that just sent their kid off to college and had a spare bedroom and some free time. I didn't work there, but based on what I saw there was a genuine focus on "non-professional" hosts. If this was an intentional ploy to fool the world, they were also doing a very good job of fooling themselves too.

I'm not debating that professional, non-resident hosts were and are the majority of the platform, just that it wasn't the original intent.

It was a huge focus of their early marketing, to the point where I was surprised to find out later that people were just renting out the properties vrbo style.

It's also quite literally in the name - 'bnb' - which necessarily implies the hosts are there with you.

I agree with the reasons for their success, but I don't believe that any of those alternatives allowed you to book a room/couch in someone's apartment. They were merely ways to either use properties for vacations (VRBO), semi-hotels like beds and breakfasts, or just regular renting space (Craigslist) for short/long term. Not the same thing as AirBnb at all.