They are not designed just for that. Modern gpus are aimed also to content creators and 3D artists and when someone buys a gpu not just for gaming, but also for video editing, rendering, streaming, etcetera, there are more aspects to consider when choosing hardware, beside frequencies and power consumption. Same goes for the cpus.
The workstation lineup shares 90% of the specs with the regular cards and many artists and professional studios since years prefer the regular ones because of the higher frequencies and cheaper costs. It's the case of the GTX 1080 and of the RTX top solutions. If you work with Blender or C4D, for example, you look at them, not at Quadro and Tesla. Those are cards optimized for CAD and scientific environment, but nowadays the high end consumer cards have workstation power and capabilities.
And still, looking at AMD cards from the gamer-only point of view, NVIDIA with the Tensor cores and the NVLink bridge beats them, no matter what.
The upcoming AMD cards have to beat these features, or at least offer equivalent (and very close in performance) hardware solutions, otherwise in specific tasks and games will fall back.
So, in the end and as for the current state of things, the NVIDIA cards offer a better overall performance value for the money, because they grant terrific performance in different scenarios. While the AMD consumer cards don't have the same capabilities and don't have the same kind of support that certain software houses offer to NVIDIA.