I might not have been clear enough about me liking windmills. I do like them as my inner nerd and engineer person. You know, "hey we built this cool device to capture the wind and turn it into electricity!" An similar example would be my mechanical watches, sure I could get a quartz watch for a fraction of the cost and it is better at keeping time. But I like the mechanical ones because they are cool and have tiny gears in them and keep the time for me with no power other than me moving.

On a large scale practical business perspective, presuming they don't have a payback at all, then well they should be avoided.