My only experience is with the off-road desert crowd. I don't think I have ever seen a door deployed as a patio. Usually people drop the door to unload gear and then put the door back up to keep the elements out.
On a TH larger enough to have a separate garage I've see people sitting in the garage. But the door is just down as a ramp and not out as a deck.
If you think about it, the ramp as a deck is at trailer floor height with no steps to get to the ground. So it can be a big cumbersome step to get down.
I suppose if you screen the door to use as a patio room and keep the bugs out it might be nice. I have no experience there as there really aren't too many pestering bugs where I live.
If you're not going to screen in the door then you might as well just put your chair on the ground in your campsite.
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2001 Suburban 4x4. 6.0L, 4.10 3/4 ton **** 2005 Jayco Jay Flight 27BH **** 1986 Coleman Columbia Popup