I understand what this is. What I don't understand is what is the purpose of doing it.
It is wildly impractical to not have an OS and have to manually program your computer every time you boot it. But don't you want to try it?
That depends. Do you want to avoid the Thompson back door? Maybe a 6502 or an 1802 with flippety switches and blinken lights can be verified not to be compromised.