I am leery of any tire pressure monitoring system which screws onto the tire valves externally. They hold the valve open and must seal against the valve opening to keep the air in the tire, which just seems like an invitation for leaks (which they would detect, of course
). Also, adding an object to the valve then spinning it around at about 800 RPM (205/75R14 tire at 100 km/h) seems like a fundamentally bad thing to do to the valve.
The auto industry's solution is sensors built into the base of the valve, inside the wheel - now found on essentially every new car - but that is presumably too expensive for the trailer industry.
: I had not heard of the Dill product before, and not followed the link yet when I first posted. Apparently there is at least this one properly configured system - thanks for the info, Tom.