When trying to match films, it seems the catalogue uses just a random date from P577 to display and possibly match items. For fairly unique titles, this doesn't matter that match:
but for others it can be a bit confusing, especially if in some countries it's released much later.
Personally, I use MIN(YEAR(?d)) in sparql.
To see what's available, I went through some of the films on this filmography.
I noticed that many entries were already matched (great!). There seem to be two fairly large film catalogues that haven't been matched and might be hard to do based on the information not available (notably lack of year). If someone is interested in doing them and this is possible, maybe this should be added. I noticed a few odd matches where the title was correctly matched, but the years were completely different (I undid those).
I will try to improve existing Wikidata items for films with the identical titles in English and year (there are some 500) and possibly provide you with an easy way to retrieve them. This way, if, at some point in the future, someone wants to match a list of films, it might be easier to do this with mix'n'match.