Question about binding off (re: Pimlico Shrug)

When one is binding off, is there a preferred way to do it when you will be picking up those stitches for ribbing?

I am binding off on a knit row, but it looks like maybe binding off on a purl row would be better since I will be picking up those stitches on the knit side.

Does it matter? Has anyone noticed a difference if they have done it both ways?

This is for the Pimlico Shrug (from Knit 2 Together), if anyone has already made this.

Any wisdom or insight is much appreciated!

It would be easier to pick up using a purl BO, but yoy could also do a ribbed bind off, and that would work great, too.

I’m unfamiliar with the pattern, but I’m wondering why you need to bind them off if you’re just going to pick them up again? :??

You’ve got a point. Why is that?