I believe you to have a much narrower interpretation of interstate commerce than Uncle Sam does, but be that as it may, there are (at least) four parties to the

I believe you to have a much narrower interpretation of interstate commerce than Uncle Sam does, but be that as it may, there are (at least) four parties to the transaction: you, your counterparty, your bank, and Coinbase. Do you think it is likely that all of them are in California and only California? You're also picking at one thread of a regulatory tapestry. Even if you are successful, there are a lot more threads.