Hi Eric -- Thanks for your question. As an owner of a murphy bed, I would say there are 3 main additional factors to consider for this use case:

• Thickness of the mattress -- Wall beds tend to have a maximum thickness they can accommodate. I've seen this be as small as 7" and as high as 15". So be sure to research this before you choose a wall bed, and if you already have a wall bed, make sure you know what it can handle. You may also want to build in some additional buffer for a comforter or other bedding that you might want to leave on the mattress when it's stowed.
• Weight of the mattress -- Once again, wall beds will vary on how heavy a mattress they can handle. This has to do with the mechanism for raising and lowering the mattress, so it has nothing to do with how much weight is on the mattress is when you're sleeping on it. In general, medium to lighter weight mattresses tend to be better, though I have seen some wall bed designs that recommend a minimum mattress weight as well.
• Floppiness of the mattress -- You'll be storing the mattress vertically, and in most cases, the wall bed itself doesn't do all that much to hold it in place. So you'll want to avoid mattresses that are particularly floppy. All-latex mattresses as well as those with a gel grid or a lot of memory foam tend to be among the floppier.

I hope that's helpful.