I've always just tied my lures directly to the line.  I've just wanted to keep the presentation of the bait the best it could be.  Beside the fact that it's easier to change lures, what are some benefits or swivels and snaps?

Swivels are used to eliminate line twist.

The benefit of a snap is that you can switch lures without having to retie.  I have fishing ADD and switch lures constantly.  Especially since I use only one rod -  I like to be able to throw a follow up bait quickly if I'm getting follows but no committments.

Never have used either, tie directly to the lure. As for follow ups, I now carry 4 rigs most of the time, no less than 2, 1 always has a t rigged worm on it.

i never realized swivels eliminate line twists.  i've always just thought they were for leaders.

The use of swivels and snaps should be determined on what you are fishing for.  As most here are freshwater fisherman I found it really makes little difference and there is a lot to be said about the line twist and ease of changing lures.

For those that fish saltwater different "rules" apply based on your target species.  Any novice saltwater fisherman or someone planning a trip shoot me a pm and I'll pass on some local knowledge.