I know it took a lot of code to write. And I know you convinced yourself it's an advantage. But it's not.
It's making people run from your site.
Look at the comments here, and these are from FRIENDLY people. Many many many others will see that in your blog article, and decide not to sign up for an account, and you'll never even know.
They won't write an article, they won't email you, they'll just decide you're skeevy, and abort.
You're already working with one tech that people thing is a bit "iffy". That means you need to do EVERYTHING POSSIBLE to make EVERY other bit of your service seem 10,000% above board.
Asking for bank login credentials, EVEN AS AN OPTION, torpedos that.
You're probably thinking to yourselves - "Maybe we should make the Credit Card primary, and make this secondary?" Just don't.
I know you spent a long time writing this, and I really wish it were a good idea, but I'd really suggest you just comment out the feature.
You can always put it back in a year or three if you really really want, once your service has inertia, and is already more trusted. But even if Square or Stripe asked for that, it'd scare people away, and lose customers. It's just a bad idea right now.
I want you guy to do well. Please kill that feature.
[1] since we're on the topic of finance
"Protect your Online ID and Passcode. You should always guard your Online ID and Passcode from unauthorized use. If you share this information with someone, all transactions they initiate with the information are considered as authorized by you, even for transactions you did not intend for them to make."
Sure, why not.
1. http://www.bankofamerica.com/onlinebanking/index.cfm?templat...
I only know of one other service that asks for bank account usernames and passwords: mint.com. And they frequently have to deal with customer concerns about the security of doing so, even though they very explicitly say they only provide read-only access. Your service doesn't even have that guarantee.
So: drop the username and password thing, and only support the standard verify-two-small-transfers option that every other service uses.
I'm not saying I would trust giving my bank details out in general, especially with these bitcoin businesses, but I have to say that when I wanted to open a business account with paypal and I was faced with either waiting days or instant verification, I took the instant option even while knowing it was probably a bad idea.
If you're looking to get users into the door more quickly, you could borrow a page from LendingClub, who will let you deposit from a credit card, but only when opening a new account, not afterwards.
That said, you should absolutely ensure your security is top-notch. You should also be getting frequent public security audits.