This typically means one of two things:
1. You've never really looked at the features added in the Python 3.x release series, or
2. You develop abandonware which plans never to upgrade any part of its platform ever, for any reason, and so no conceivable new feature would be sufficient to convince you to do an upgrade.
At this point (1) is untenable because of how many people have written about the useful things available in 3.x, and (2) is disingenuous (but there are still plenty of people who use "don't see a reason to upgrade" as an excuse for "I always planned to abandon this").
Just in case you're one of the people in (1), here you go: