Indeed. 500€ bill was known as "Bin Laden" because it was so hard to find one. It was estimated that 90% of the bills were held by drug dealers, money launderers and other criminals.
They're gorgeous though. Because they're so low circulation, when you do get to see one they look brand-new. My father got one from a currency exchange this year and when he mentioned that I had to take a picture of it: https://imgur.com/a/aiaZmP2
Edit: I suppose since it was an exchange outside of Europe, they probably wanna put them in circulation before they lose legal tender status.
They will maintain their legal tender status. ECB just stopped printing more and existing notes will be removed from circulation when they enter the banking system.
