Absolutely nothing wrong with Craft Paints - lots of people use them extensively...many people use them exclusively, and while they have draw backs over hobby paints - there isn't anything crippling about them.
The can be a bit thicker than hobby paints - but that is a non issue. I know a few people who paint at extremely high levels who paint with tube paints. You can thin almost anything down far enough, and the added benefit is that if you are thinning the paint, it does mean you actually are getting even more for your money.
The bigger issue is generally the pigment density versus hobby paints. Many of them are a bit light on pigments, so when applying them...especially over stuff like a black primer coat, it can take a couple more layers to get good coverage. The easy fix is just don't use a black primer. Over white - they generally cover fine with about as many layers as you would apply with a hobby paint.
The last bit is that they can be a little "chunky". With metallic and what not - your flakes are large...very large, and can cause problems in airbrushes. With other paints - they can have a bit of grain to them almost. It isn't the pigment itself that is the issue (most use liquid dispersion pigments just like you find in hobby paints) but a coarser grind on the matting agents and additives to increase opacity. In is sort of hit and miss on that though, one bottle will be smooth and the next bottle of the same color is a bit gritty.
Nothing comes close in terms of price though (except paint by the gallon from a big box store). A 2 ounce bottle of Apple Barrel costs about 60 cents. If you shop smart, you can get them down to around 40 cents a bottle by picking them up on sale or using the coupons that stores like Micheal's and Hobby Lobby have every other week. Even looking at it from Dessorag's perspective - you are saving a good bit. 7 2 ounce bottles for the price of 1 12ml bottle (discounted at 30%) from
GW...
For what craft paints look like on models...here are a couple painted with them:
A few years back Jen Haley painted a couple miniatures using craft paints just because...and there really wasn't anything that set them apart from her regular work. Meg Maples started using Craft Paints and did a similar experiment too. Like a lot of us though, they continue to use hobby paints because of the lack of hassles. In some ways it is why people moved away from enamels to acrylics - not because acrylics are superior, but because they are less work.