The nature of this question and the way you are asking it suggests that you have heard about ESIGN and read manuals and other digested discussions about ESIGN, but not actually read the ESIGN act. Once you know what you're going to find, the legaleze isn't such a formidable barrier. The concepts underlying ESIGN are really very simple.
ESIGN doesn't regulate banking products--directly or indirectly. It exists for two purposes:
1. to legalize digital signatures, and
2. to provide a means for businesses to use electronic documents as the legal equivalent of paper.
If you want to use digital signatures, that's entirely a business decision--ESIGN offers no help (or hindrance). It doesn't define, limit, authorize or prohibit any particular technology. When disputes arise, you will have to make a convincing case to the court or regulator that, in fact, the customer has "signed" something and should be held to the terms of what was signed. ESIGN simply tells the federal judge or bureaucrat that the concept of a digital signature can't be dismissed out of hand.
If you want to use electronic documents as a substitute for paper documents, that too is a business decision that you and your customers must make. Like digital signatures, ESIGN tells the federal courts and agencies that this medium cannot be dismissed out of hand. If you choose to provide e-documents to consumers, ESIGN prescribes a type of "handshake" that tests and validates your technology in advance. It requires nothing if you want to provide e-documents to businesses.
ESIGN doesn't permit you to force customers to accept e-documents when they are entitled (by a federal law or regulation) to receive those documents "in writing." Other than that, there are no truth/fairness/equality requirements or hidden "traps."
_________________________
...gone fishing.