In my mind the only places where an A frame house makes any sense at all is where very large snowfalls occur. The design works well in that one situation since the snow will slide off the roof. There is just to much lost space from the steep side walls formed by the roof line.
I built one in California back in 1970, I was amazed at how much storage and living space was lost because of the roof line.
I stayed in one at Squaw Valley Ski Resort that same year, it was ok but not a great living space. It did shed the snow quite well though. If I lived in "snow country" I would most likely have a modified A frame, with straight walls for the first floor, there would be open space that way between those ground floor walls and the roof line which would be great for storing snowmobiles and other things.
The classic A frame is spaced 16" on center and the really good ones have one piece Joists from bottom to top of ridge. This distance can be so long that one piece joists are impossible to find.
Yes it is very strong and you can (with good knee-walls) make use of almost all the interior space. The thing that most people find inconvenient is the roof line forcing one to bend at the neck or waist when in the loft area.
I've seen many modified A-frames where the ground floor is straight walled then the A-frame mounted at the top of this and carried down to ground level. This give two eave spaces for parking or other uses.