First of all, get the RTX 2060 GPU, if possible.
Anyways, both GDDR6 and HBM2 are made in a different way, and they excel in different areas, and enterprises. For example, the high bandwidth of HBM2 is ideal in situations such as AI and advanced computing, HPC, Compute. This is why we’re seeing it in data center GPUs, such as Nvidia’s Tesla V100, where the cost is less important.
On the other hand, GDDR6 can offer a lot of the same performance, albeit with higher power requirements, but at a lower price. This makes it much more accessible for the everyday user, hence we’re seeing it in commercial consumer graphics cards.
As far as GAMING is concerned, both types of memory found their way in gaming graphics cards as of late.
However, we cannot say that one type of memory is better than another for gaming because there are a lot of other factors that come into play. Things such as bus width, base clock, and boost clock all matter, and you can find graphics cards with identical memory types performing differently from one another due to other factors being different. There is one advantage that HBM2 has here, even with the higher cost. The fact that it has a lot more bandwidth means that you’ll get better performance and less latency.