They are using scan tools to get the temp. About as useful as installing temp senders in the combustion chambers.
in what way? It's reading the sensor in the thermostat housing, so I don't know how you get any more accurate understanding of when the thermostat is opening.
Ultimately what we care about is whether the non-uniformity of thermal expansion of block and head are going lead to a warp or crack, but the coolant temperature is the best analog we have for that short of Chrysler spending insane money on a bunch of instrumentation on a model they mostly seemed only interested in cutting cost out of.