I can imagine some people cringing at the thought of using mains cable to connect loudspeakers. I do recall an article in a hifi mag in the late 80s (may have been WHFi but can't remember) where 5 cables were tested/compared. 4 of the cables were recognised speaker cables, the fifth was mains cable. The results showed that the mains cable performed better than 2 of them.
I don't use mains cable now for the speakers but did for many years, so I can only say that it will work just fine. As regards what speaker cable it could be compared to, I've got no idea.
Rich