As one of the nutters who bought a Vega GPU for gaming, I'm probably in a better position than most to explain why someone might think it's a good idea. For a start, I bought my GPU on launch day and for some reason, it was on sale below RRP. At that point in time, it was similarly priced to a GTX 1070 while giving similar performance. However, as I intended to use an adaptive sync monitor, once the price difference between a similar Freesync and GSync one is taken into account, the AMD route worked out cheaper. Now crypto mining has inflated the price of AMD cards, I'm not sure if it works out like this anymore, but now is a bad time to be buying a GPU if it can be avoided anyway. There is also the matter of Gameworks titles tending to work better on a previous generation AMD GPU than a previous generation NVidia one and many other smaller issues that would potentially have swayed me towards AMD in the case that both companies had similar offerings at similar prices.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT