"The first order of business is to build a group of people who, under the influence of the institution, grow taller and become healthier, stronger, more autonomous".
Robert K. Greeleaf, Servant Leadership
Coaching as a management style can certainly be of immense benefit when working with a functioning staff to develop employee potential and long term strengths. A manager who possesses both the ability and talent to coach employees in how to be more resourceful and self-generative goes a long way toward nurturing future leaders for succession planning, with an added benefit of increasing project management effectiveness through delegation.
However, not all situations are coaching appropriate, especially when the business unit is faced with crunch deadlines or when on boarding clearly calls for a situational leadership approach. At other times, a managerial coaching style will be less effective when the leader must make tough decisions about people and risk being unpopular while carrying out organizational directives from above. In these cases, a managerial coaching style won't substitute for a manager's ability to achieve the organization's goals. Discerning which management style is best suited for what occasion and successfully implementing it is truly a best practice.