We use them quit a bit around Lilly pads. Both with a clear casting bobber to get the offering close with a spinning rod, and with a fly rod. I've never used them to sink, but I don't see why they wouldn't work.
I used to do some trading with an ole boy that ran a baitshop out of his house. Actually out of an old train car at his house. He used to make some "ants". They had floating foam bodies, rubber band legs, and he used copper wire to tie the body on. This wire allowed for just the right amount of sink. Man were those baits dynamite. He never sold any at the shop. One of those "my little secret" type of deals. Cast them with a clear casting bobber about 5 feet above the ant. It sank really slowly and the crappies and gills loved them!