That looks useful in the core as outside the peaks, most of the passengers will be leisure travellers. It would also be beneficial in the peak with loading indicators operating as the dwells will be quite short, and on narrow platforms such as at Farringdon, once the train has drawn in, there's not enough room to quickly shuffle up and down the platform to get to the less loaded cars.I'd been planning to write a post here about the mystery platform zones in the core section. For as long as they've been there they've not been used in any way as far as I can tell.
But today at Farringdon I've noticed train diagrams now feature on the digital screens. Presumably at some point they'll show loading indicators too.