I use them all of the time.
Now keep in mind that there are several sizes.
There are switch plates which are so heavy that I leave the one I have at the place it is used and use it for coon alone. I really don't like it all that well as I can't toss it far enough to get where I want it. I have to carry it out in the water and drop it where it goes. This one is used for a drowner weight.
There are the regular sized ones which make wonderfull drags when you use 2 of them together on a long (6 foot) chain.
Then there are those baby ones that come off of the small tracks that I don't think anyone uses anymore. They have to be used with care and NEVER just one.
If you use too light of a weight, the coon may take it up in a tree and tangle it up there and that sucks the big one. I have seen a 45lb coon take 2 regular ones up a tree just far enough to make it rather hard to get it out compounded with the fact that we had no gun that day.