[nickpsecurity]

If it's CompSci, it lets me know if it's an older version of a current work or an updated version of older work. I like to skip the former in many cases to go straight to the final, polished paper. Whereas, the latter keeps me from skipping a paper whose preprint or initial results I already read. Without a date, I might think it's the same paper.

I'd say it's even more important as a search aid. I run through hundreds of papers looking for the next dozen or so worth submitting to a wide audience. Search will bring me results that span decades. Dates in prominent places help me quickly filter or discover stuff depending on what I'm looking for. For instance, I was looking for CompCert-like projects getting results going back to the 1980's. Verification of realistic, low-level programs didn't get feasible until into the 2000's. So, I immediately filtered anything before that time. Where the date shows up also varies depending on what kind of site has the article. And you bet people might have not thought about this use case when publishing their papers in the 80's. Yet, the standard practice of dating the stuff still helped me.