Yeah, but sand people use slug throwers.

Though there’s no canonical information about the speed of blaster bolts, they are very slow on screen. You can follow them with your naked eye.
You can’t however see or follow the slug thrower’s bullet that might even travel at super sonic speeds.
Leading a target is much easier the less time a projectile needs to reach it.

However, sand people and stormtroopers train with different weapons on different targets for different situations. So it is very possible that sand people are generally better at shooting longer ranges with high speed projectiles, taking wind speed, gravitation, coriolis effect, etc into account while stormtroopers are superior (and more precise) in hectic, close quarters situations where you have to aim and shoot quickly.

That being said, nobody checked for continuity while making the prequels anyway. And Obi-Wan is famous for talking about things “from a certain perspective.”