alt Hacker NewsJoule is a derived unit, it is kg*m^2/s^2. There are lots of derived units, like hertz and newton, because they useful than writing out the whole thing. Electronics would be really annoying if had to write out volt, ohm, and watts (ampere is base unit, coulomb is derived).
Don’t put words in my mouth. I only said that power should be J/s instead of watts. The “per second” part of that is what is most important thing about power. It’s the rate at which energy is accumulating or being used up.