I'm not 100% sure but i guess they are managing the company from Malta without having any Maltese employee. I don't see how Maltese tax administration could verify if the director is actively working for the company. They could guess "well you don't have any employee, you are managing the company from Malta so surely you are doing all the work" but they need to prove it, do they have the manpower to go after you? They are getting 5K tax without doing anything.
Also, all businesses need a help from somebody, you can't do it all alone so you could pay a freelancer to help you out and show invoices to anybody that question the fact that you are actively working from Malta.
That's 100% true.