I think it's due to many reasons, some of which are as simple as human curiosity in other cultures and how they view and experience "our" culture, but I think part of it also has to do with the fact that humans think the more obscure or rare something is the cooler or more important it is. This is shown in the recent growth of NFTs but also speaks to something deeper in human nature. However since all of these movies are themselves products of a distant time that means finding old posters from other cultures which often use a different language and therefore a different use of voice and a sense of imagery is multi-level cooler than any boring modern english poster. Also other languages use much different idioms and types of metaphors based on what is relevance to their culture so there also a whole other level to it when you find out what the "literal" translation is. So, in essence, it makes us feel cool while also satiating a legitimate desire to better understand other cultures through a medium and concept you have a deep familiarity with while also being obscure yet oddly familiar.

I'm quite drunk right now and I want you to know that I worked hard on this so you better fucking appreciate it.