Ballistics for Hunting

Hunting with a rife has quietly changed in the past couple of years. You can get a laser rangefinder for a hundred dollars, and a smartphone for "free".
There was a time when, out of ignorance, people would come up with rules of thumb for zeroing. Wind was ignored.
Nowadays you can measure range exactly, look up the ballistics table on a smartphone or luggage tag, and make the correct adjustment to your elevation turret.
If you are still guesstimating, why?