Repetition of common misconceptions
It's a common misconception that pair programming is only about programming (probably it's badly named). It actually combines lots of activities that have been found to produce better code - refining requirements, discussing implementations, reviewing code, extending the test coverage.
Even the most experienced programmers can find new ways to look at problems, and spot problems or blind alleys that they might have missed working by themselves. Pairing with a more junior programmer isn't about dragging someone else along on your coat tails, it's about having an open discussion about the problem that you're solving. And even the most junior programmers can ask questions that make you reassess the implementation that you first thought of.
But these are the things that you only find out if you actually try it.