You raise an interesting point, but I think my critique is more along the lines of theories of qualia being nonfalsifiable. It’s an attempt to show that the “problem” of qualia is a linguistic puzzle. Any comment we make about the “existence” of qualia is not giving us any new information about the world, because it has no testable implications. To use your computer analogy, it would be trying to talk about hardware issues in a computer in a world where we could absolutely never observe the underlying mechanics of the computer. Of course, with our human brains, we can get a sense of mechanics through science – but we can’t get at the “essence” of our minds with philosophy, and qualia seems to be an issue of the “essence” of experience.

That is because functional descriptions are abstract. They are not full causal explanations. A functional description of a computer systems need not mention the need for a power
supply, or any other hardware issue, but computers need power to actually work.

If you have a full causal explanation of system S that omits property P, then you can safely
conclude that P is not necessary for an actual implementation of S. But you can’t conclude
that computers don’t need power, just because hardware details are omitted from an abstract high-level functional description.

So your argument doesn’t show that qualia are redundant. They might still be part
of the hardware implementation that implements and drives the functioning of the system.
(As they would be under qualiaphilic identity theory).