Eh. Feels a bit of statistics ping pong. Reduce car use isn't a very precise term, and they even quote them in the article as meaning a reduction IN THE AREA where the LTN is.
I love the ones near me as a cyclist and pedestrian. If you want fewer cars you have to make driving more annoying (I.e. less convenient) and more expensive, end of story.
Hardcore car commuters, the kind of people who vandalise LTNs, and vote only about more cars/roads in London are kind of addicts, I feel like.