Should 300 GSM toothed water color paper be used for pencil colors?
A lot of color pencil artists use watercolor paper for their work because solvent blending is less likely to damage the paper from any moisture that may be added and the paper can take a lot of abuse since it is so sturdy. However, most of the ones I follow use hot press rather than cold press or rough. 

It's true that you want tooth, but cold press or rough has a lot of tooth and it can be really tricky to get color into the valleys of the surface. This may lead to needing a lot more pressure to fill and wear harder on your pencils, requiring more frequent sharpening to maintain a sufficiently sharp point.

Still, not all papers are the same, so if you have some and want to try it, you may appreciate the look you get and prefer it. In the end, there is nothing that says you can't!