Awww, JW I bet your ears are better than that tuner.
Jamming with different people, you don't need to stop and tune in between every song. Playing live you don't have that opportunity unless you want to kill the show.
Half the time its not the guitar, it's the player pulling strings out.
Every thing you play, you have to do with intonation in mind. Just listen to a jr high band compared to a high school band. They all tuned to A 440...
They also learned to adjust to make the horn section sound as good as the woodwinds.
This is where the whole string thing comes back into play, because it has a fixed intonation, and the string wear constantly changes. I hate tuners because there is no way to explain to someone that yeah your open string is matched and in tune, but when you play a triad on the 8th fret your guitar is so off because your strings are so old and your ears and talent are not good enough to compensate.
I have a tuning machine I walk around with. Its an A440 fork. God am I old fashioned.

Don't argue with a stupid person. They will pull you down to their level... And beat you with experience..."Samuel Langhorne Clemens"