[maro]

That's just a limitation on the implementation of the architecture. You're right, a four-state logic is not practical with current technology. So what? If we had good four-state logic, nothing FUNDAMENTAL would change. Presumably, our computers would get faster by some factor, but so what. Personal computers today are much faster than PCs of 5 years ago (Moore's Law), but nothing FUNDAMENTAL about personal computers has changed.

[Southack]

"The intrinsic base 2 design of the hardware is used to represent numbers in hexadecimal, or base 16. ... So what? If our hardware was configured as base 4 using four distinguishable voltage states, nothing about our computer technology would change."
...
"That's just a limitation on the implementation of the architecture. You're right, a four-state logic is not practical with current technology. So what?" - maro

Four state semiconductors would permit an exponetial increase in the number of workable potential circuit branches, as well as process data and instructions more than 8 times as fast as the maximum potential speeds of today's circuits.

To data processing, that sort of breakthrough would be roughly equal or analagous to a new jet engine that permits speeds of up to 16 times the sound barrier while burning less fuel than a Volkswagon Beetle per hour.