The rationale is that it kind of applies radial forces in varying directions when you rotate the wheel, and if there's any tiny slack between the hub and the wh

The rationale is that it kind of applies radial forces in varying directions when you rotate the wheel, and if there's any tiny slack between the hub and the wheel, helps make that slack 100% concentric while the wheel is still able to slide against the hub. But honestly I do that simply for the peace of mind :) A soothing personal idiosyncrasy inherited from my dad.