It can be a smart thing to do; it depends on the situation. If I'm able to successfully run a lot of different kinds of businesses and am willing to choose what business I start based on what kinds of businesses venture capitalists are willing to fund, for example, I may be eliminating my primary comparative advantage by being specific about the kind of business I want to run. (Of course, I can also reframe this as a two-phase operation: in phase one I gather information about what kind of business it's best to propose, and in phase 2 I propose it specifically. It's just that sometimes phase one and two occur within five minutes of one another in the same conversation, and the results of both are discarded for the next conversation.)