I like that you can make your calls from anywhere! You don't have to be at work when it's time to call someone back if they are unavailable during business hours (which happens all too often).
It would also help out greatly if there were an app so we could see what our coworkers are doing while not being able to talk to them directly because of this restriction feature. This has helped us keep better tabs on each other as well as how much overtime everyone puts into their jobs due to certain projects needing extra attention than others. We're now always aware of who needs support whether it's through emailing one another about something specific or just keeping up to date with things going on around here.