I'm not exactly sure how anyone would believe marketing hype where a company says they can do something a LOT harder than what Intel, nVidia and AMD have yet to achieve with just CPUs and GPUs
I see no 10nm CPUs or GPUs in the near future, and Bitcoin mining is a lot more power intensive and thus a lot more difficult to manufacture workable chips.
Yet they're boasting jumping straight to 7nm ... ... ...
There's also google-able reasons (related to power issues) why there are no 10nm CPUs and GPUs yet

I think you need to read between the lines of what they are saying: A 8TH GPU SLOT card for 300W... e.g. An ASIC card that fits in a normal PC GPU slot. At 300W the PC case cooling system SHOULD be able to handle the heat.