What GPUs do you use for game development with UE4?

I have a GTX 980, so that’s CUDA GPU already in my rig right now. I don’t want to buy a Pascal card and I am hearing that Volta won’t come to the consumer market. I am buying a Vega 10 (RX Vega Nova as the name goes from AMD).

So in that case, how are these cards “Professionally” used (the Vega FE and Quadros)? Is it only about AI and machine learning?
I just want to know more about GPUs, but what I am confused is why is AMD marketing this card to game developers, when the whole Star Citizen team, i heard, has GTX 1080s in their rigs (i thought they have Quadros!)