One reason to pair is to observe how other people work. So I find it invaluable. Even if its how someone else uses an agent.
I also find it useful for educational purposes. In the olden days, that would mean a senior coaching a junior. That's still relevant for most non-trivial tasks, even those that involve an agent.
Pairing also helps two people share a mental model for some code. That becomes the kernel of shared team understanding. I still think that's relevant, even if we're collaborating on a PRD an agent uses.
And frankly, I still think its useful to ocassionally read / write code. And another human in the loop helps a lot with that.