Either you use it or you dont. It is good to use it though, make it a good habit. Plus, I want to announce to those around me especially when I am backing up into a garage: I am here, do not stand in my way. If you dont use it, obviously you can cause accidents.

That being said, there is a 3rd group who I absolutely fucking despised:

Those who use it just to show the cops or whoever the fuck around that “look, I use blinkers”

When changing lane or enter a turn, uually this type of driver will go Click-Turn-Click. No head movements whatsoever. Also turning the signal off immediately like the sound of it can cause them brain cancer or something.