It is Ideal when...  

You are starting a company and do not want to be burdened by the cost of setting
up a permanent office.
You need to organize meetings in the city frequently but do not have the budget
for a physical office.
You work alone or often travel and a physical office is not necessary.
You work from home but require a professional address and corporate facilities for meetings.
Your business lends itself well to operating in a virtual environment.
You want to test the sometimes turbulent waters of the business world first before you sign a lease for office space or get a mortgage for a building.