I'm most impressed by you folks who can read abc from the page and turn it in to music in your head fluently.
I've always assumed it was there as a simple text form for sharing a tune when pdfs or photos were not an option.

I think I've found it most useful via mandolintab when I've wanted to create a midi in a different key.
Or change the line breaks.
Or change the font size.

For me the snag with being given a piece of paper(\pdf) with the dots is its lack of adaptability.