(I'd put it somewhere in the 3 - 5 cents range if you take enough time).

You could use it as a backup in those aggravating times when all you have is a headstock clip-on and the noise level is so high that your guitar is picking up sympathetic harmonics out the wazoo: enter the light-based tuner, and problem solved

Works as well as tuners that sell for well over 5 times as much

If you need to do non-standard tuning, you'll have to use the strobe against a fretted string; for Drop D tuning, for example, you'll need to fret the low E at 2 and use E6 for comparison.