Agreed, with JMB, you always need a miter saw.
The TS saws, they can do miters but setting it up is complicated and time consuming. Frankly, it's a waste of time if something as easy as a miter saw is around.
Jigsaws, no way, I would never use them for my precision miter cuts. You can get marking errors and errors because of the blade wandering all around.
I myself have no miter saw though, but I use my CS70 portable table saw for most of my miter cuts, but it sort of is a miter saw. I use either the CS70 or a handsaw with miter block.
But I'm just an enthousiast hobbyist. If I was a full time pro I would definitely have a dedicated miter saw also.