I don’t understand why they wouldn’t just use the original posters. These are still in English so it’s not a translation thing. Are there licensing issues of the US artwork?
Whatever it was, I'm pretty sure it wasn't licensing issues - I guess the movies (or VHS tapes, going by the references to "video clubs" on some of the posters) themselves were pirated, so they wouldn't have stopped at the posters. It's probably more lack of access to the original posters, or lack of equipment to reproduce them (except via painting)?