Does an alternate grip provide an advantage over a pronated grip on a deadlift?

You'll find out when you get strong enough to pull a whole lot of weight.

It's not an advantage, it's a necessity. At some point your grip strength won't be able to keep up with what you can pull, and you simple won't be able to hold onto the bar to pull it off the floor.

HOWEVER, until then, it is suggested that you stick with the pronated grip because that is an Excellent way to improve your grip (i.e. your extensors and flexors around your wrist), which is useful for many exercises.