seller's personal banking details

[S B]

I work for a large bank, and have access to everyone's personal finance data including information about their current mortgage.

An investor buddy of mine said something like 'What I wouldn't give for THAT kind of priveliged data!'

Now, I know right from wrong, and I would never take the risk of using that data nefariously (awesome salary, beautiful family) but I am naturally curious about what one could do with that info. I can't ask him because he was joking and would tear me up if he thought my questioning indicated that I was seriously considering it.

So what advantage would this info bring you?