Interesting question. My question again would be why?. You just transferred the responsibility from you (the SaaS company) to a well known processor. This doesn't make a data breach or data sharing avoidable/impossible.

Also, anything related to finance is always hot. And this comes back to the same thing I made in the above comment, why should an end user who is just trying it out risk all of this? It's like telling a stranger a secret of yours. You wouldn't just share a secret with a stranger just because they say "trust me", would you?

It is the company who needs the users attention, not the other way around. The users shouldn't be punished for the same.