"Reading all that makes me so sad. So if I want to play games and do 3D graphics/modelling/etc I have to sodding buy two gfx cards, and/or two separate computers to go with them? bloody hell!"

No, you don't. You only need a certified gfx card (workstation card) if you need ISV support for your professional application (and this often requires using a certified workstation like those from Dell or HP, and using a certain combination of drivers). If you're doing that for hobby then a gaming card works just fine with the majority of professional apps. You just miss a few features and won't get ISV support.

Similarly, if you need a workstation card then you can also use it for games. All you loose is a few fps over the Geforce/Radeon equivalent of your workstation card.