These "walk-and-talks" create a dynamic feel for what would otherwise be long expository dialogue...Dynamic feel? A feel of perpetual artificiality and irritating restlessness more like it. And thanks to Olly for the term, entirely new to me, 'pedeconferencing'.
I'm sure it's time for a further development of the idea. When one character comes up to talk to another, the two of them could pick up musical instruments and accompany their own dialogue; or she could stuff a doughnut in his mouth and one in her own so they could have a chewed conversation. There'd be no end of dynamic variety.