I can see it being a slight irritant, as (based on your profile) you are 1K and they might have had 'plans'. During my flight last week while ordering meals, the purser kept insisting I was 1K and "got my first choice no matter what".
I never really pay attention to seat assignments when travelling with spouse (no status). I messed them up a bit a while back and we were in 1E & 1F and I took the window. Apparently I had us switched on the reservation because they double-checked and asked me to confirm which of us was the 1K. Actually it was when I was ordering an old-fashioned and they got a bit confused and then the light went on, "ohh, YOU are the 1K! they are the ones that usually ask!" I apologized and said I must have done the seat assignments backwards...
Point is, several times when recognizing my status, I have seen it matter. Beyond that (and maybe drink charges in the back) I doubt they care that much.