I would agree that all Scripture is equally inspired. I don’t believe that it’s all equally clear. There are some parts of Scripture that are much more difficult to understand than others.
I’ll go to the brink of heresy for a second to make a point: it’s not all equally important. Now, Jesus never spoke a desultory word, and everything that God reveals is important. But it’s not all equally important.
When He reveals to us that Mary and Joseph went up to Bethlehem, that’s important so we know that it fulfilled prophecy and all the rest. But that’s not as important for us to understand as the gospel is. Of course, both parts of the Scripture are inspired. There’s no degree of inspiration.
I think what the question means by “applicable” is that not everything is equally important in its application to our lives. To know about David and the census is significant. It has historical significance, but not the same significance as the account of Christ’s crucifixion.