Reasons why king and rook mate quicker than king, knight/bishop and bishop? When I was very young I remember learning the point values of the pieces. And then I ran into something very confusing.

I was able to learn king and rook vs king mates pretty easily, but king and 2 bishops was trickier--and bishop/knight took me much longer to learn.

This confused me. B+B/B+N = 6 points > R = 5 points. So I did not understand why the rook did things more quickly. Was it just me seeing things linearly, or was there something about how pieces interacted?

I have some ideas for how to express this simply, but nothing concrete. It seems like there should be such an explanation.
King and Rook mate faster because the 2 pieces coordinate better together.

Recall that the mating procedure for King and Rook is about making a box with the Rook, then making that box smaller. This is quite straight forwards. Compare this to mating with King, Bishop and Knight, which is hard even for masters!

This brings me to discuss your misconception on the point value of the pieces. They relate to trading pieces. So if you trade Rook and Pawn (6 units) for 2 minor pieces (6 units), then on a point only basis, material is even.

Note also that the point value system is a guideline. It is not a cast iron law of the universe. In the example above, which side is better after trading Rook and Pawn for 2 minor pieces depends on the concrete position. But that is a different topic.