I have never dried my own cars but my dad and grandfather insisted on towel-drying cars to avoid water spots.

Though come to think of it, a leaf blower might not work for that, unless it's actually managing to remove the water mechanically and eliminating evaporation. I recall mechanized car-washes using blow driers so maybe this does, indeed, work.

You're from a great line of dads!

When you wash the car properly, you want to remove the excess water as it's not clean. Most people do this with a microfiber, towel or chamois. These can scratch the surface if not done properly.

A strong blower will remove the water without scratching the surface. It also works in places too small to reach with a towel.

These same dads insisted I clean the wheel covers because my small fingers could get in the details better :-)

They were car guys, my grandfather got best of class iirc at the concourse d'elegance for a 356 in the eighties. Now I own no car (but many bikes!)

There are also something called "water blades" - soft strips of plastic/silicone that can be used to sweep water off car surfaces.