We use snap swivels, too
For the reason you list - quick change of jigs when looking for the "right " crappie bait. Some guys like a loop so their jigs aren't tied rigidly to the main line, and I kinda think the snap achieves that free-floating affect. It may also make a difference that we cast-and-retrive almost exclusively when fishing for crappie. I do tie direct for bass or cat fishing, though.
I like the idea of having multiple poles rigged, but here in Ohio, we are limited to two poles and if the ranger finds you with several rigged poles at hand, you will get fined. - Roberta
"Anglers are born honest,
but they get over it." - Ed Zern