I've been curious about them, but honestly I don't trust the connection as much as a good cave knot.
The knot is not complicated. The cave line costs pennies... or, for the cost of two of those DiveRight retainers, ($5), you can buy a full spool at a hardware store that will last the rest of your life. It takes a couple of minutes, and you're done with a connection that will be good for YEARS.
How often (if ever) do your bolt snaps need to come off? Do you really want to risk a $4-12 bolt snap with something that could potentially get knocked off, just to save yourself a couple minutes of knot tying?
As intrigued as I am, instinctually, about neat gadgets, I just don't see a place for these on my rig. I want to set my bolt snaps in place ONCE. They really never get moved again... and if I do, again,
cave knots really aren't difficult. It's just an overhand knot and a square knot, a couple of loops, and a lighter. If you can't tie a square knot while looking at directions, perhaps diving shouldn't be your sport...