In many cases how is it different from visiting each page and printing/saving the html? It's useful to create a backup of the site[1].

I'm not saying it's good or bad. It could be used for both. I know at my previous job we used it (a bit shady I think) to scrape and compare competitor prices to ours.

[1] Though I can't understand why you'd want to backup your own site but I am pretty sure I've heard of it being done.