This is where things gets fun. You know what the most common punishment I see for driving without a licence is? Being banned from driving.
That's because from memory, it's a more serious offence to drive whilst banned than without the correct licence type.
One is a pure motoring offence, the other is wilfully ignoring a court order, and if you're caught breaching any court order it tends to result in much harsher penalties.
So the initial ban is there in part to open the way for additional punishment options.
It's the same as the punishment for a lot of offences might only be a court imposed fine, but if you refuse to pay it you end up with the possibility of spending a few days in jail (for what might have been a £75 fine originally).
It seems slightly mad at first, but there is a logic behind it.