I think the skills a person would have such as medicine, craft blacksmith,ect. do not quite translate into actually making a living in the world. While a person with Medicine 10 would be a excellent doctor, and could easily cure vast numbers of ailments, this has no impact on her being capable of procuring supplies that she needs, charging for cures at the appropriate price, and in general running a business of being a doctor.
Could the doctor hire a business manager so to speak? Yes, and that person could for a price run the business aspect. Or even a family member could do this for them and roll the cost into the general expenses for the family.
A black smith that is really good at his Profession Metalcraft score, could possibly only have basic knowledge of working metal, but hires a number of workers with great metal working skills. His money would be made based on his ability to run a smithy, not work the metal.
I think the Profession skills are the skills of earning a living at something. The skills you use within that profession are not necessarily as simply as a specific skill.
Just think, your profession is say tailor. You are living in Constantinople or Basil or Paris, and you have to find customers amongst the clergy or nobles. Sure your skill in the craft would be important but no matter how good you are, if you are unknown, few elite would buy your wears. The skills of intrigue, charm, and etiquette would also be very important in procuring contracts or sales.
I guess the way I see it is Profession is a cover all which you use for seasonal advancements, money and such, and direct skills such as the craft, intrigue, folk ken, bargain, ect. are for in-story or covenant book keeping. In the end though I can see profession as a catch all for simplicity sake.