Then add a dollar to every microwave, washing machine, fridge, doorbell or other device with a hint of processing that uses a small embedded processor. Optimising transistor gate count for simplistic application is absolutely worth doing, even if you end up with an architecture that doesn't happen to be the same as expected by people who have only ever programmed for x86.

The assumption that 'a byte is eight bits' is less specific than 'a character is one byte is eight bits' but I think captures it pretty well and affects at least all the people who are affected by RTL writing, I would think.

If anything, the one character -> eight bits problem was so large huge amounts of work has been put into developing and using libraries that abstract the representation of text away from byte streams.