On the other hand, putting it into an email gives a chance for people to digest and think about it offline, for the person who was travelling that day to be able to see it, for you to be able to forward it to the team who's working on the UI across the Atlantic from you.

Face to face communication definitely has it's place, but it can also lead to cliquish and insular behavior, and can lose out on some benefits of having a paper (well, electronic) trail.