I have to confess having never tried the salt technique. The results I've seen don't appear very realistic to me, but I understand that many guys do like the look it provides. The problem as I see it, and again I haven't used this technique, is the wear doesn't look very realistic to me.
A few years back I tried several techniques using dissimilar paint types. Of course I tried hairspray and generally like it. I use it for more than just chipping to show metal. For chipping to metal, I think I like the scalpel technique better. It's certainly more controlled.
This is Hasegawa's 72nd Oscar. It was painted silver using Tamiya enamel aluminum, barrier coated with Future, and sprayed very randomly with a Mr Color green. While the green was fresh, like maybe 30 minutes after spraying, I chipped the green using a #15 scalpel blade and a light touch. Chips can be removed with the desired shape and at the desired position. The black was Tamiya's acrylic black and was too fragile for chipping this way. Touch ups are easy though and actually look better. Corrections add depth to the finish. I really liked the appearance of the finished model.
A modeling buddy likes to use the masking tape technique when he wants massive chipping. Again, dissimilar paints, a barrier coat, and a fragile final color coat. He then wads high tack masking tape in a ball and presses the tape in a random pattern. He then sharply pulls the tape away. This leaves a nicely chipped surface. This works really well for a highly chipped subject, but it's not as controllable as using a scalpel. It is much quicker, though.
These days, I generally use hairspray and chip with a dry toothpick or an abrasive erase. The final coat paint adheres to the hairspray. The hairspray doesn't really adhere to the paint layer below. That is at least not initially.
I also like the sand stick method. Here the top layer is abraded using a fine sanding stick. This really is more a wear technique, but it can also chip paint. This works better with another chipping method. Again, we're talking depth of finish here.
There are other methods as well. We all have ways we like best. I won't tell someone not to use salt if that look is what they like. It just seems to have be random to me.