currently on the interview trail for PCCM, the interviewers have focused more on what research I've done and where I went to school (AMG vs IMG vs FMG) and making sure I was a normal individual.
However, they have all made a big point of the USMLE scores (I scored very well on all 3) and openly admitted that it matters because it reflects how hard one worked as a medical student. But, it seems to be secondary to the other aspects (research, residency, letters)
It would seem to be a screen for competitive applicants and then something extra.
The appetizer and the cherry on top but not the main course, if you will.