And most of that is from the script to Broken Bow which in turn lifted wholesale from the description in the show bible. Seems they forgot he existed after the credits rolled on the pilot.
I'm all for keeping Trek casts to essential characters. Both voyager and ENT had characters they didn't know what to do with because they just filled a spot in the crew roster. TNG did this a little bit but could have been worse (the rotating helm ensign is the right way to do superfluous seat filling). Only really TOS and DS9 were largely immune to it.
TOS had the advantage of not being an ensemble show. There were the three lead actors and a gaggle of bit and day players filling recurring supporting roles.