The only type I've ever used was a Revell enamel based one, back in the early nineties.
I used it on my Hero Quest Skellies (what can I say; I was young, and I had the money
). I still have those minis, and the finish was not great; kind of chalky and had loads of lumps in it.
It's highly probable though, that the paint simply contained the same powder that 6milPhil was referring to. It made painting smooth layers of it nigh on impossible by brush, and any type of airbrush would clog almost immediately. But that was nineties tech, and enamels never were a good choice for painting models in the first place. Good chance that modern powders are finer and easier to use, with better end results too.
The good news though, is that, to the delight of my 6 year old, they still glow in the dark, even after more than 25 years!