No offense, but your view that, "since a lot of people match even before taking/submitting Step 2 you can guess as to it's importance" is simply the conventional approach. The NBME allows one to register and take the exams independently. There are several circumstances this could bear witness to, only one of which I will mention.
Since many programs look at COMLEX, if you are a DO student having taken COMLEX Step1 and 2, you can apply through ERAS and receive several interviews at allopathic institutions, without having USMLE scores in hand. Later you could improve your chances at those and other places by taking USMLE.
So the question still holds - what bearing does Step 2 have vs. Step 1 on matching decisions, presuming in this situation, you have at least completed COMLEX?