I think that this diagram is a good starting point...
https://media.licdn.com/mpr/mpr/shrinknp_800_800/AAEAAQAAAAA...
Blockchains allow me to build economic protocols that require scarcity without inserting myself as a middleman to enforce that scarcity. This is where the most potential lies. There are lots of problems that exist because the transaction costs to solve them are too high: finding someone to solve them, agreeing on a price, and setting the terms for when something goes wrong can be cost-prohibitive. Each time a new economic protocol is built, mankind is permanently given the power to trade frictionlessly in that arena. This is a new thing. Join us in figuring out how to use this new thing.
It's a class of fiscal blindness in the same category as the people who are positive gold is a great investment that will always retain it's value (it won't, the existence of a spot gold price proves this trivially).
Those regulations don't apply to peer-to-peer electronic cash transactions, just like they don't apply to physical cash transactions.
edit: there are also regulations that apply to physical cash transactions if they are over a certain amount.
>And trading derivatives contracts on a blockchain would almost certainly violate US laws.
These laws will eventually be made obsolete, the same way obscenity laws were made obsolete by the internet.
If you become an Electronic Money Institution, in most cases you'll still have to follow KYC and AML laws. Bitcoin companies in the EU all do after certain thresholds.