Is there any point to have two separate documents - A4 and A5, if the content is the same?

Hi guys, I recently purchased some documents (pdf) online. I was surprised to see exactly the same document, but twice. One hd “A4” and second “A5” as files’ names. I opened both and they were identical. Does it make any difference when we print these documents?

My impression always was, that if I want to get A5, I simply need to print 2 pages per one A4 sheet.

I’m a bit confused after that purchase, especially that I also sold some dogital files and I never sent my customers A5 version assuming, that it would be identical as A4 anyway.

could you please let me know whether it makes any sense and difference to save the same document separately in A5 and A5? Are there any benefits of that?