For the most part,
Workstation cards (FirePro, Quadro) are good for high precision and accuracy applications, like 3D modeling/drafting, complex simulations, biological modeling, etc. In these types of "productive" applications, people want accurate results most of all.
Gaming cards (Radeon, GeForce) are good for quickly pumping out "rough" geometries. We think of new videos games as being high quality, but in reality, the polygon count is still pretty low.
Workstation cards might have error correcting (ECC) memory and additional high (double) precision floating point units. Those type of features are a waste in a fast paced video game, but not when you need to render something much more complex.