In Leslie Perlow's work sustainability speech for Big Think, she discusses how it is detrimental for people being constantly connected to work in all times of the day.
With so many factors that go into client management, there are legitimate reason why a person would want themselves to be constantly connected to the work. A client might call or have a question, and these factors cause people to cultivate a culture of constant responsiveness, which then trickles down to every person involved. This creates a certain expectation around the work environment that people require one another to be ready all the time with no exemptions.
Perlow states that it's important to cultivate a manageable work system that will permit workers to have times away from work. Forcing employees to take time off will actually make work more fulfilling and efficient.