The difference would just be how you think of the process. I sometimes shuffle around the numbers to make math easier, but the shortcut for adding 9s just feels different. Instead of 9+7 = 10 + 6, it’s more like 9+7 = 17-1. It feels less like solving it with math and more like using a cool trick, since you didn’t really use addition to solve the addition problem.
I’ve always felt like people were overblowing the pocket lint thing, since I’ve never had it happen to me. Just realized that it’s because my pockets are too small, so the only pocket I can use is my back pocket with the port sticking out.