Well, the 12-string has its good points and bad points, right? Good point is that it has a unique sound which is very rich and melodious.

Bad point is that you have 12 strings to change and to keep in tune! And it can feel a bit cumbersome compared to a 6-string, specially if it's not set up quite right.

But some people love them, and for some it is their primary instrument. I think that's the case for Gordon Bok, who plays an Apollonio 12-string. Gordon Lightfoot has used a 12-string on a fair number of his songs.

There's a woman in my local area who plays nothing but the 12-string. She has an utterly superb Taylor 12-string that plays like a dream, being perfectly set up, and she plays it very well. I owned a Guild 12-string for a while, a great big heavy jumbo guitar, and I found it interesting, but never got too good at playing it. Eventually I took the octave strings off, and played it as a 6-string instead. ;-) Then I finally sold it to someone.