1. We think the extensive usage of the original bed icon in wayfinding signage around the world makes it something that most users have already "learned". Most people take that icon to be representative of hotels since they've already seen it so many times.
2. We debated the building approach, but we thought it may get confused with the "home" icon. And we didn't want to use icon+text in our design at this stage. We think the buildings approach gets even more confusing without a text label.
As I said, however, it's a bit of a subjective choice...
I think the bed icon clearly demonstrates what you use a hotel for - a place to sleep. This encompasses hotels that aren't several stories tall as well.
And no, I have no idea why flight plus hotel equals desert island with palm trees...
However, outside the context of other reservation-related icons, I agree that the "building" icon is lacking in specificity. The bed icon is slightly better, but still by no means good. It could just as easily mean sleeptime or rest, as opposed to daytime or work.
It's a shame there are no symbols or architecture inherently associated with hotels. Maybe that's why they tend to feel so anonymous and devoid of any soul...
The distinction here is that you don't get in an airplane to sit in the seats, you get in an airplane so it can fly somewhere with you in it, and the shape of an airplane is very good at conveying that. With a hotel, I don't go there so I can admire the building, I go there so I have somewhere to sleep.