It has always been difficult to meet the super specialists like Cardiologist, Oncologist, Urologist (or any other specialist). Even if you get to meet the specialist, the interaction time is so little that you hardly get time to clarify all your doubts.
Specialist Opinion Service enables you to ask a question to a Senior Cardiologist or Oncologist or a Neurologist (and many more specialists) and get a reply from these specialists.
This may be an important service if someone known to you is already diagnosed with a serious problem and wants to talk to a specialist to get his second opinion.