Well, they consult you. They setup the company for you. They give you the license and they lease you the space. And they don't do it as middlemen.
There is a setup fee (2k$ I think), co registration fee and yearly license fees. They're the same whether you have them help you or go though an agent, or not.
So, basically, having them hold your hand does not cost extra.︀ And there is no advantage in approaching them via a middleman.
In a non-trivial case︁ I was involved in, they even got a legal opinion from their own legal counsel︂ specific to the case, free of charge. Nice, smart, business-oriented people.