Regarding the flats/sharps tuner, im guessing the original logic behind this is that the most commonly used keys in “guitar” music are G,C,D,A,E (probably in that order) hence the CAGED approach, therefore using keys that employ sharps rather than flats so, dealing “musically correct” with these keys, there are no flats in these keys only sharps.
However, as for tuning, more often than not, we tune the instrument down and think in terms of “flats”
Thought for the day- do you “tune up” your guitar or “tune down”.
One is a common phrase and the other is a common choice....
Ps. Happy Christmas and No complaints with the latest implementation
For me, I think of it like this, On a 6 string guitar what's the fat string called? Answer: E. when I bring up the tuner & hit that string I call E, I don't want it to read D, I want it to read E. Same with A,D,G etc. Has nothing to do with keys, just quick tuner reference.
I have and will knock my guitar WAY out of tune and when seconds count between songs I don't want to have to think "OK my G string should read A#" I want my known string letter name shown.