We don't actually store your credentials. We work with Plaid.com, and take a token which we can use to pull balance information. This allows us to fund a transaction in real time and take on the risk of ACH. When you change your credentials, that token gets reset.

If we took routing / account numbers, you'd have to preload your account and wait up to 3 business days. It's something we're definitely looking into though as well though.