You have to convert USD to some cryptocurrency at some point, and vice-versa, so that's what they'll regulate.
Money changed hands for me to get that currency -- money paid to the power company and to a few eBay sellers for video cards -- but nothing requiring an exchange fit-for-purpose.
If purchasing with cryptocurrency ever truly becomes a thing (yeah, I know it exists, but it's rare and becoming more rare these days), that will affect the other side, as well.
Willful money laundering isn't a "simple" risk-reward decision.
Unless you're pushing tens or hundreds of millions of dollars around, they'll probably tell you to go pound sand.
The SEC will be interested in the exchange and its staff. The IRS will be interested in individual users' bank transfers.