So if an aerodrome doesn't have equipment that does the averaging it's probably appropriate for a FISO to say that it's the instant wind.
LookingForAJob, good point!
That said I get the feeling that surface wind readouts go in one ear and out the other with quite a few pilots.
Recall in the 1970s at EMA where a C150 was doing circuits and ATC were saying "Clear touch and go, wind scrambled eggs" - we were all listening in at the flying school. When said pilot came in the ATC rang to have a word and asked him "Do you recall what wind I was giving you when I cleared you to T & G/land?" He had no recollection!
Mind you when I see that state of the wind measuring devices at some GA airfields and wonder about their calibration I wouldn't hold my breath as to how accurate they are.