"Not approved for road circulation" usually means flat (not convex) and/or too small.
They might work anyway, but with a more narrow view.
Seeing behind you AND to your sides isn't possible - you have to choose.
(I choose behind and then do the head check to my sides)
I do get both views of side and back with my bar-end mirrors. I got cheap one from China on ebay. But depends on my lane position, I do see what behind me and to the side. However, I like moving my head and check to the side as I'm switching lanes though.
**did not mean to thread-jack OP** just my $0.02