When you have a sales email address that receives a high volume of emails, your sales reps would not always be able to respond to all the emails assigned to them. If the emails are made visible to everybody in the team, then sales reps can simply choose emails that haven't been responded to and send replies. So the next time someone in your team is away from work, his emails don't have to wait until he arrives. People in your team can take turns and reply to them. Your Team Inbox becomes the common room for all the sales reps to read and reply to emails that your company receives.