Your bargaining position is much better once they've already decided they want to hire you. Talking about salary first lets the company cheap out and only spend that effort on people they are reasonably sure won't ask for what they're worth.
This is why so many places have a "Salary Expectations" box or something similar on their interest form. Some will even try to brow beat you into saying a number. Never do this until they've named a number first. This puts pressure on them to offer something reasonable right off the bat, instead of having the pressure on you to not ask too high.
The strategy is meant to introduce more sunk costs in the hiring process. They spent forever buttering up the candidate, and now they hear a number that is more than they were hoping for.
The less they need you, the less this is likely to matter. But if they really need you then of course your price is high!
This is why so many places have a "Salary Expectations" box or something similar on their interest form. Some will even try to brow beat you into saying a number. Never do this until they've named a number first. This puts pressure on them to offer something reasonable right off the bat, instead of having the pressure on you to not ask too high.