Your phone locks for your safety. If someone were to steal your locked phone and didn't know the password, then it'd be a useless hunk of plastic to them.
I've already discussed how valuable the ability to lock and remotely wipe your phone can be, but remote locking and wiping has left Samsung smartphones with a new, major security flaw.
A bug in Samsung's Find My Mobile app - which normally helps you find or remotely lock your phone - could let a hacker reach into your phone and remotely lock it. Worse yet, the app gives a random password to the person who locked the phone.
So that means a hacker could lock your phone and ransom the code back to you. Or, worse yet, they could just throw away the key.