If Coinbase is going to report earnings to the IRS, it's a good idea to match what they report or you might trigger the algorithm.
So I think the manual and automatic processes are considered to be two forms of the broader term "audit".
"An audit may be conducted by mail or through an in-person interview and review of the taxpayer's records."
"You will be provided with a written request for specific documents needed."
"An IRS audit is a review/examination of an organization's or individual's accounts and financial information to ensure information is being reported correctly, according to the tax laws, to verify the amount of tax reported is accurate."
Consquently by my interpretation (and actual experience over many years) your last sentence is not correct.
Also there are some borderline issues with taxes (and/or self employment or small corp) that can give you problems. (One for example is deducting for a home office, another might be charitable deductions, another might be writing off some auto usage).
Think in terms of what happens when you see the flashing lights of a police officer in back of you. Even if you haven't been speeding you don't automatically think "no problem I didn't do anything wrong" you get anxious thinking there might have been some mistake that you have made.
 See the typical business owner isn't Zuck and doesn't have an army of knowledgeable advisers to handle all the details. You are essentially on your own with your accountant.
And sure, 1 in 1,000 is nice odds, but you're still breaking the law. And some people care about not breaking the law on principle.
Also, if you do something the government doesn't like, then they can retroactively investigate you and bring the full force of the law down on you for tax evasion, which carries harsh penalties.