Well what's the point of any lock? At first glance you would say, to keep someone from getting in. But that is not the whole truth.
Any lock can be broken, picked or circuumvented somehow. The question is, how much of an obstacle should a lock be. Even in our non-magical world there are different kinds of locks.
- On a bathroom door, you just have a simple lock, for the purpose of telling everyone that it is occupied.
- In your house, you might have simple locked doors to prevent children from getting into rooms they should not.
- Then you have a rather sturdy lock on your front door, that should be too much of a hassle for a thief to get in. It only needs to be strong enough so that is about the same effort to break that lock like smashing a window.
- If you have valueables at home, you lock them in a safe in the hope that you would get home before someone breaks that lock (or rips the safe out of the wall).
- A bank stores its valueables in a rather large safe with a complex lock, so that armed robbers don't get in too easily.
The question should not be "What is the point of having a lock that can easily be broken?" but "What do you want to protect from whom with a simple lock like that?" and "Can it deter an offender from trying to break it?".
In the magical world, obviously, a mundane lock could only provide simple privacy from someone who is not willing to open the lock.
If you want to secure something better, you will have to put charms and wards on the lock, so that the unlocking charm will not work. Obviously, then you could just use bombarda and blast away the door (or the wall next to the door). However you'd at least have a clear sign of breaking and entering then.
If you want it to be even more secure, you would then have to protect against THAT threat and so on... Like in our mundane world, it is simply a question of how much effort will you believe someone is putting into getting past a barrier you've set (like is it worth blasting open a wall to get an inexpensive item behind it).
Allright, obviously that doesn't even work well in our world, since thiefs will be willing to cause several times the damage in property to what their loot is worth in the end. But it is just the same compromise you will have to make.