Very practical, that's how some backhaul works(and why you see giant microwave dishes on mountain towers).

This Ars[1] article does a great job covering what goes into it. I know of more than a few WISP out there in WA state. They can't do the same data rate as fiber but getting a connection is pretty straightforward if there's any large mountains nearby.

[1] https://arstechnica.com/information-technology/2015/11/how-a...