and I can break your smart phone code by looking over your shoulder while you press the numbers
a lock only keeps a honest person out.
any password, any code, any protection scheme can be hacked any anytime.
By that logic, should I not bother locking my house gates, since anyone with the right tools could eventually get past them?
Of course nothing is foolproof in this world. The idea is that you can at least make it hard enough for crooks that it serves as a viable deterrent.