This is key: "The speed of the floor panels of the express walkway vary between each end allowing for a slower embark and disembark speed but a higher speed in between to decrease journey time"

Other moving walkways are limited in speed because of the differential between the non-moving and moving parts would make entry and exit dangerous.

This one "slows down" the moving parts on entry/exit, which is pretty cool.

Being from the Toronto area, I always assumed that these were at more airports (those with a similar design, that is – as you've mentioned, normal moving walkways are at most major airports).