I do, when I'd like to read a paper that's locked behind a paywall and not available on sci-hub. Authors of scientific papers are much like any other authors... they want to be read. The more enlightened among them understand that obscurity is a problem rather than a perk. They also tend to appreciate engagement in the form of follow-up questions (at least from people who actually read the paper.)
Obviously it's not a major concern on arxiv, but in a larger historical sense, this type of communication was a key original application of email.
If an author wants to be read then they will keep the preprint PDFs on their website (along with their current email address). An added benefit is that Google Scholar indexes and links directly to the PDFs instead of the publisher website.
I do, when I'd like to read a paper that's locked behind a paywall and not available on sci-hub. Authors of scientific papers are much like any other authors... they want to be read. The more enlightened among them understand that obscurity is a problem rather than a perk. They also tend to appreciate engagement in the form of follow-up questions (at least from people who actually read the paper.)
Obviously it's not a major concern on arxiv, but in a larger historical sense, this type of communication was a key original application of email.