We're a very distributed team and A&Os are one of the ways we keep everyone in touch.
Also, doing this Monday morning is pretty important -- it means people focus on planning the upcoming week, instead of just summarizing the week that ended. Having a time every week where you set goals for yourself, and then communicate them to all your peers, seems to be pretty effective. And one benefit of having these emails go out to the whole company is that everyone can read them and comment on what people are planning, before the work starts.