There's been several topics on this and it seems there's a pretty mixed group that support them, some that are very against them, and some that are indifferent.
I'm in the group that supports them, for certain baits. I've removed the split rings on a majority of my treble hooked baits, instead opting to use a small snap. This allows me to change baits quickly without changing the weight (action/balance), of the bait in a measurable amount. I don't do it because I'm lazy, it's efficient and I have 100% caught fish I wouldn't have if I wasn't using a snap because I'll change a bait for just a few casts that I wouldn't have if I had to retie instead. I still retie just as often, if not more, and I've never had a snap open on me.
I would not use snaps for much other than treble hooked baits like jerkbaits, lipless and lipped crankbaits, and a select few topwaters though. They work fine with some other baits, just a personal preference.