VC's have a better understanding of customers and markets than entrepreneurs. Often the assumptions a founder makes about how their product will be accepted are fundamentally incorrect. The best way to make sure that the premises upon which you are basing your theories aren't false is to run them by people who know better than you. No question is so stupid that it will disqualify a founder from receiving funding.
a cold call is a pitch, and a pitch is a story. learn how to tell a compelling story from beginning to end and you will find cold calls much easier and more profitable. this takes REPETITION