I think I can offer a simple explanation on the value of Future floor finish- essentially you are adding to the acrylic medium already in the paint by adding more uncolored acrylic medium so the amount of pigment per volume is decreased while maintaining consistency in the behavior, flow, and transport of the suspended pigment (color)... in other words, you're mixing colored acrylic "paint" with additional clear acrylic "paint" so your liquid behaves the same and dries the same as using straight pigmented liquid paint but the color is diluted and spread out over a larger area. (not sure if that was exactly a simple explanation, but maybe a more structured one). I completely agree that one of the best things about using Future as part of a "mixture" is that it's a floor wax/finish, so using it to dilute your paint is like adding a protective coating to your colors. Similar to spraying a sealer on after the fact. Particularly helpful with non solvent based acrylic paints that tend to be less hard after drying. Createx colors designed for painting cloth or some low cost acrylic paints, might be good examples of softer paints.
Personally I shy away from using Future floor finish as a reducer and instead rely on products designed specifically to "reduce" acrylics. It does, however, make for a great sealer and I use it occasionally. Ultimately, you'll need to decide for yourself if its right for your purposes.