I agree on the second point, but then again, I'd never rent my house out with Airbnb either, and apparently they've done well. Different people have different tolerances for risk.
I watched 'Up' the other day and I couldn't help but chuckle reading that. Pretty sure there were some major traffic and airspace violations going on there. It'd be harder still with a condo!
It's hard to impossible to damage your house by the renter so that the damage stays hidden. With car, it is pretty easy and the costs of such damages when you discover them afterwards would be realatively high.
It might be riskier, but most of the time nothing's going to happen either way. And I'd rather have someone trash my car, if insurance covers it, than trash my house.