I find it humorous that people think this is some sort of deception when it is probably simple tradition. Roman numerals used to be common and are still used in many places like for preface/introduction in many books, is that also some sort of deception? they could certainly used 0-<page number> for that or even a different font if they needed to separate it from the pagination of the text but they use these confusing Roman numerals instead.
Yes, it clearly started out at least partly as a prestige thing. Books (and even periodicals) indeed used to often have the publication date in Roman numerals, and the older and more self-consciously presteegious a book is the more likely it is to have them in that format. Clearly the inter-war studios were trying to claim some of that prestige for themselves, just as they added other neo-Classical elements to their branding for similar reasons: think of the Columbia logo and so on.
Including a copyright notice? I'm most familiar with post-1960s films which had both, but left "small print" things like that to the very end.
Wikipedia suggests opening credits were always incomplete credit-wise - "Films generally had opening credits only, which consisted of just major cast and crew, although sometimes the names of the cast and the characters they played would be shown at the end. " - but doesn't talk about copyright there. https://en.wikipedia.org/wiki/Closing_credits
This. You get to see old cities with a lot of commemorative monuments, and they are all with years in Roman numerals (and many of them, with the whole inscription in Latin).
Academic books were written in Latin and were dated with Roman numerals because, well, they were written in Latin.
For example here's a cover of Calvin's Institutes of the Christian Religion, 4th Latin edition, printed in 1562, with the year of edition in Roman numerals:
It probably used to be just this simple indication that this section was something different (frontmatter) by using a less common but still generally understood number format.
It did used to be more common, especially for things like monuments. But it's become less common over time. I was traveling with a friend of mine who went to good suburban public schools outside of a major city and then an elite technical school. I was somewhat shocked to learn she had never been taught (or bothered to learn) Roman numerals. Even if it's sort of a trivia thing at this point, I just assumed it was something that a reasonably well-educated person would just know.
In what sense? For the preface/intro yes, and that is still common. Before the 1950s hyphenated page numbering was very common especially in technical/educational books and the preface/intro would be 0-1 to 0-n, chapter one being 1-1 to 1-n etc, appendix was often in Roman numerals in these books and done in a variety of ways. When you get back to the ~1900s or so you also saw hyphenated Roman Numeral page numbering but from what I can tell that was never a standard outside of a few niche fields.
Edit: There was also a phase of hybrid Roman/Arabic hyphenated page numbering in there somewhere, if memory serves most of the books I have seen with that were from the interwar period, chapter/section would be Roman and page in Arabic.
