Yes, the GaNtube is done for marketing and is indeed a "fake tube". Everyone knows you could have put the circuit on plug in boards inside a chassis that you could also upgrade easily.....you just take off the cover and change the circuit boards.....but no, you decided to make it look like a tube amp by mounting the class D circuit inside a tube body. Nothing wrong with that......but it is for show only.....yes, you can upgrade slightly faster......but at increased cost to the consumer. Plug in boards on a main circuit board would be cheaper.
A Vacuum tube is a Vacuum chamber that " is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied." Your Tube is not a vacuum tube.....it is a solid state circuit inside a tube body.....therefore it is a fake tube.....it is not a Vacuum tube....it is pure marketing. Just admit it.....you did it for the "cool factor". Nothing wrong with cool factor.....some people will buy it just for its looks....good for you.....making money is good.....and you have a great sounding amp.....with fake tubes.....he he.
May you be happy and sell a ton of fake tube amps.......