And yet, it's so very, very easy to fix..
What I find baffling is that people find this a difficult problem to solve when you have a touch screen.
All you need to do is randomise the position of the digits on each PIN request. As it concerns numbers it's not too much of a hunt to find the right button (it's not a good idea with alphanumerics) and it gets rid of such detection (location sensing is also something that happens when observing someone entering a PIN on a doorpad - you can assert probabilities from the way the arm moves).
Of course, you make such an idea OPTIONAL - for the user who values convenience over security or who has reduced sight or mobility.
Also, as the video was is showing a fingerprint reader equipped phone, let's make it possible to access such a device with a combination of PIN and FP - that is IMHO better for a device that carries payment information.
Biting the hand that feeds IT
