The purpose of a discovery meeting is two-fold:
Understanding the gaps in the client's business.
Determining why they have chosen to talk to us, specifically identifying the gap between their current state and where they need to be, because if there is no gap, there is no sale.
I think effective questioning and listening will help the buyer form an early vision of two things:
The need for change.
That we are the right people to help them make that change effectively.