Water soluble oils are different.
The biggest advantages of oils, they lack IMO. For miniatures, they really lack. In order to get significant working time with them – you need to go thick
very thick. They are not particularly useful for making glazes and wet blending – the veggie oil base that they use mixes with oil, but strangely doesn't like to mix with itself.
The actual oils themselves never seem to get as hard as real oils. I have some on canvas that are over 3 years old that still feel a bit rubbery (as opposed to oils
which I could use as a rasp).
The chemistry is a bit odd as well. You can use water to mix them, but it doesn't thin them in the same way that water thins acrylics or turps thins real oils. When you thin the water soluble oils to a very thin consistancy – they paint more like water colors. If you want a thin paint consistency, you generally need to use an oil based thinner like linseed oil.
If the oils start to dry (on your palette or in the tube) – adding water doesn't help much. If they dry completely – water is absolutely useless
so it isn't much help for clean up if you make a mess or forget to clean out a brush for whatever reason.
Unlike real oils – you need to rely on additives to really make the water soluble paints work. You need to add an additive to speed up drying times, you need to add an additive to do glazes, you need to add an additive slow down drying (or go really thick), you need to add an additive to give it additional body (less important with miniatures).
Anywho, for me – I have no use for them. My wife got me a set a few years ago, since she didn't like the smell of turps. Used them a bit, didn't like them much at all. The extra work involved without many benefits over a full bodied artist's acrylic make them not worth it. If I were looking at avoiding oils – I would go with a full bodied acrylic.
For miniatures though, since we don't want to be able to see brush strokes or paint an impasto landscape, there isn't a whole lot that I like about them. I use oils on miniatures to wet blend. They don't wet blend. To make the wife happy – I switched to odorless turps when I use oils in the house.