Luckily the locks all operate manually too, although I think the filler flap manual release is in the boot.
Where central locking is fitted, the tailgate and passenger door unlock automatically when the driver's door lock is turned manually with the key, as does the petrol filler flap. So there's no benefit except when you have passengers or luggage and when you fill up with fuel. You do get a reassuring whirring sound though when you unlock and lock the driver's door to remind you of your car's little luxury.