I don't..... understand how you could get milk from almonds in the first place.
Secondly, for people that don't like milk....why would they want to drink a milk-like substance? 
One thing is that "lactose intolerance" that some people have, now, they are able to remove the lactose from the milk.
They have a Flax Milk, good Omega 3s in it.

Some of these are pretty good when they flavor them, usually as chocolate. Vanilla too, though, regular milk, I never see flavored as vanilla.
So, there are probably indeed, a few reasons, people might prefer alternatives over milk. I wish "raw milk" was readily and widely available. It's suppose to be very good for you but has some drawbacks as to storage, not being pasteurized, etc.