I also carry a Mora as a neck knife. I find the #1 or #1260 to both be good sizes for neck carry. I have them attached to a rawhide bootlace tied in a fisherman’s knot so that it is adjustable as to size of neck loop.
The Mora can be worn with a tucked in shirt and drawn through the neck of the shirt if you adjust he loop so the handle is just below neckline.
I started carrying neck knives during the summer on the lakes since with no pockets or belt in a swimsuit there were a limited number of carrying places. You could also be wet up to the waist with out having your knife wet.
Chris is correct about it being an ancient carrying method made new again. Some American Indians, Nordic peoples and several nomadic tribes found this carry method useful for their small utilitarian work knives.