'Q' was probably only used to be distinctive, with no real meaning, any more than the military used 'Z'. I doubt very much that many of the code groups were ever self evident, but of course after the event you can dream up anything to fit. Q codes were not just questions since the meaning could change between transmission and reply, one meaning "Am I...?" and the other "You are..." or "What is?" and the appropriate reply would be prefixed the same. IE QDM - "What is my bearing" and "Your bearing is...." and no doubts about whether it is from/to, magnetic or true, Spanish or French etc, etc.
Such code forms were, and may still be, necessary to ensure quick and umambiguous interpretation of critical information. The use of the word 'altimeter' (not uncommon in the 'States) is a hazard if the recipient doesn't know if it really means QNH, QNE, or QFE and transmitted between persons without a common natural language. There were also several other Q,s for altimeter. The use of Q code is clear, easily used and unambiguous.
Q code was not limited to W/T nor three letters. Teletype time was much improved and clarified by the same form. NOTAM code was (is?) Q and came in five letter groups. This may illustrate the point, since a single group could explain the whole NOTAM irrespective of the language it was decoded in. I can't recall any proper code groups, typically something like QNBOS might mean Q-(use the Q book), NB-(NDB) OS-(out of service), and would do so in English, Russian, Chinese or anything else. Some two-letter encodes were self evident but most were not.
Not everything the Ancients did was stoopid.