The instrument I actually do play is the mandolin. I love my electronic tuner because I can tune up all eight insanely tight strings without hassle in a noisy pub or at the edge of a session. It may not be perfectly accurate, but neither am I, and if anyone in that pub or session can hear the microtone of variation from A440 I'll be very, very gobsmacked.
Forty-odd (very odd) years ago, I was tuning up half a ceilidh band with a tuning fork. The electronic gadget is infinitely better.
Besides, all instruments strung in courses are very slightly dissonant -- the jangle of the unequal strings tuned to the same pitch is what makes them sound the way they do.