I love how much good debate chairs encourage.
I'm firmly in the camp of "if it's not comfortable, it's firewood". I also have several part-finished designs in my head that may be another decade or so before being actually made.
Many much drooled-over designs are impractical and poorly made, cars, furniture, the lot. The constraints of time, cost and quality occurred back then too.
Setting is an interesting point, IKEA furniture can look a bit naff by itself, but a room full of it looks just fine, same for most I find. Deco is the only exception I've noticed, one piece alone can be enjoyed, a room full is often overpowering.
As for the mackintosh chairs, you'll need a large room with a high ceiling, or they turn into room dividers, but I can see them working in the right situation, not sure they look comfortable though, a few years ago I wanted some, not any more.
Aidan