Any use for watery paints?

Right now, I'm working with some hand-me-down paints, which are a mixture of different name brands. A couple of the name brands seem to have more of a watery consistency no matter how little water I use. Right now, I'm loving working with the creamier paints, like Wolfe. I'm thinking of replacing all of the watery paints with creamy paints, but I'm not sure if I should keep the watery paints.

Are watery paints good for anything? Or will they be redundant if I replace them with creamy paints?

Thanks!

I don't quite understand the "watery" description. Is it that they need to be worked up into a more opaque state to paint with (some paints seem to have a bit of film on them when brand new, and you have to work With it a bit to get satisfactory coverage at first), or is it more a glycerin base which is better for sponging, but not really line work? If you give the brand & specific color, somebody may be able to give you better guidance...