We prepare beforehand, and end with specific action plans and assignments. The results depend on how well we prepare, and how committed we are to designing assignments that are high-impact and doable. Together, we identify high leverage activities, and do what it takes to turn them into results. I haven't found so. In fact, it is often more effective.
People can talk about sensitive issues more easily by phone than they do in person.
The lack of visual feedback is generally more than made up for by the increased openness of the conversation. Consulting is advice-giving and data collection. It's one way, with accountability on the consultant for delivering. The only obligation on the client is to pay in a timely fashion. It's about helping a person design the life they've always wanted.