I had a good friend staying over Xmas. She's a very talented professional artist, and took a real interest in the mechanics of my figure painting. Although she uses acrylics all the time she'd never even seen, much less used, a wet palette. And she suggested that the paints we use might be the same as she uses, just a) in much tinier quantities, and b) much more expensive!
Interesting….my first dabble with acrylics was using artist heavy bodied paints on a wet palette. I got the wet palette idea from an artists text book borrowed from the local library (very much pre internet days) at least thirty years ago. Daler Rowney, who’s user base is rooted firmly in the artists camp, have been making a commercial one (stay wet palette) for at least as long, but I was too cheap to buy one as a trial so used the book idea to make my own LOL. There are many additives available to the artist as well. These enable them to modify the heavy bodied acrylic paint so it performs as they want it, but I never got it to work well for miniatures painting. I went back to Humbrol paint and oils paint until the early 2000s when I restarted the hobby. Great paint for scenery though.
I would say that artist acrylics and modellers acrylic paints are similar, but not the same. Theirs are formulated to mimic oil paints, so are too thick to use on fine detail. Ours are formulated to brush paint smoothly, and latterly, to work well through an
airbrush (though that’s still open to debate).
i found artists acrylic invaluable when painting a flaming sword on a miniature balrog for a mate though. Being able to get the paint to stand up was excellent for reproducing nicely textured flames, and the high pigmentation made the yellows and reds cover better than any hobby paint I’ve used.
As to costs, look at the price of some Artist quality oil tubes and you will change your mind. Some of them come in at over 40 UKP for a 40 mL tube
I suppose it must be possible to thin artist’s acrylics for spraying through an 
