While I definitely think that the FNX 45 tactical is worth the extra money, I don't understand your implication that aftermarket threaded barrels don't exist for the FNX 45 as EFK firedragon makes them.If you're already a good shooter, with sound fundamentals, then the red dot option will make you a little better and more consistent.
The threaded barrel is worth the extra money by itself. Take a look and see if you can find an aftermarket threaded barrel for the fnx 45. You'll be looking for a long time.
Oh, the cool factor. .. Nothing more BA than a tac.