The article says 'The other method used is to simply pull the lock out of the plastic housing.' and they show other locks fitted.
So, as far as I can see, those plates alone won't prevent theives opening the door?
No, but it addresses the most common, quickest (and least obvious to bystanders) method of entry. You are talking about brute force attacks.
You could also fit additional deadlocks, slam locks, etc. etc., turn your van into Fort Knox and end up spending half an hour unlocking it every time you wanted to get in or out, but it still wouldn't stop a determined thief who had decided they wanted to get into YOUR van. What one or other of these preventative measure may do is to make a speculative thief think it could be easier to find another van that hasn't got them fitted.
You have a very solid half of a bike lock in each door. OK, it's not apparent from outside, which may confuse a thief or even prevent entry, but not stop an initial attempt, because its not obvious to him (or her) that the measure is there until he's tried.
Suppose he was really intent on getting into your van rather than anyone elses? He might then decide to try a crow bar,peel the door frame down around the window or just cut through a side panel with a rotating saw.
Me, I'd probably just smash the glass and climb in!