I think that it would depend on the jig - one time use, multiple uses and, more important, whether it needs to be adjustable. I have both, and the onetime use jigs are made for function and not appearance.
I bought the Kreg jig for drilling cabinets for knobs and pulls, strictly because it could be adjusted for different centers, adjusted for different edge distances, etc. - made sense rather than taking the time to drill holes in pieces of plywood every time you needed to install hardware.
I have an old version of the Rockler Hinge Crafter which I've mainly used for smaller hinges, a Milescraft jig for larger (door-type) hinges but that always struck me as a little hokey in the way they said to line it up for location - I needed to hang some replacement doors, one of them directly on the studs as the original owner had done, and made the jig shown so I could screw it to the studs and rout the recess "in place". I probably overbuilt it, but it will work for me anytime I need to install 3-1/2" hinges.
The jig for routing slots was cobbled together when I was making my adjustable height workbench, but I've used it since then on a couple other projects, the length of slot is "adjustable" by putting a block in the opening to limit router travel. As you can see. it's pretty minimal, I would have made it look prettier if I'd realized now useful is was going to be.