its not about filesystem vs database, where the data is stored is arbitrary, its about how much information you need to access it, apart from the increased entr

its not about filesystem vs database, where the data is stored is arbitrary, its about how much information you need to access it, apart from the increased entropy in using 2 bits of information (a username + a password (depending on the link size)), you can also implement things like locking accounts when someone guesses the password wrong X times, something that is impossible with a single entry point.