Earlier quoted context omitted.
500 Euro bills show up in action movies as part of shorthand for shady dealings. Like a visual cue that something is not on the up-and-up.
They seem to be of most use to rich people who want to hide assets from the tax man by carrying the cash across the border to Switzerland. Probably doesn't work as well as it used to anymore though. A few years back I talked to a guy from norther Italy who said most people had a second bank account in Switzerland to hide money from the government.
Unless you have unclean cash to clean ofc