Hard enough documenting a routine once, why do it twice?

Because it's different documentation for a different audience. POD is used the generate manual pages, aimed at the user. Inline comments are for the programmer. Not making a difference means at least of group of people loses.

It's like the difference between the instruction manual that comes with your car, and the book the mechanic uses.

I never inline POD. For several reasons; to name a few: POD wastes a lot of valuable screen estate - I rather see more code. And I seldomly want to document functions/methods in the same order as I define them.