Having the tuner be scale aware where it would:
Display the note as it would be represented in the key so show a Bb in appropriate cases instead of always showing A#
and/or
differentiate between in-key and out of key in-tune notes where tuner is only green if note is in key.
The cognitive load of doing the translation of notated B in a key with flats showing A# in tuner is correct and notated B showing B in tuner is sharp and out of key gets annoying when working with vocal stacks and trying to hunt down an off note.