Two observers at same location but driving different direction measure a different physical clock display event of the 4D clock located at a distance.The point of that discussion was that if it's physical, it's four dimensional. And if it's three dimensional, it's not physical.
The converse does not apply. Just because it's four dimensional, that does not mean it must be physical. The definition of "physical" that we are using is "measurable". You have to be able to run an experiment. One cannot measure the future (except by waiting -- and then it's not the future any more). That means that the block universe does not qualify as "physical". It is, as @Dale refers to it in #256, an "interpretation".
That's measuring a 4D object, be it a 4D clock, or the 4D universe/block universe. What else would above measuring be?
What then is an object if it's not 3D, nor 4D?Edit: Calling the block universe an "object" is also a bit of a stretch.