I was asked many times whether I use swivel or not to tie jigs. I use both. When I need to change jigs often, I use swivel as illustated below and I tie directly if I have to hurry or I stick to one jig for a while. Even I tie jig directly, I don't see much problem of twisting lines. The other option is to tie jigs directly and use swivel 6 - 8 ft above jigs.