Exactly. That line is very important. In reality, he had an idea for a product and an existing market he had direct access to. That "less than a week" bit should really include the time it took to build the audience in the first place, which is probably a lot more than a week. A somewhat disingenuous claim.
Learn to write apps in 10 minutes! here the source code for an hello world, to learn anything else it will only take the rest of your life.
Most founders have an idea, decide it's something they would like to pursue, then spend many weeks/months working to validate it, build MVP, attract customers. You can't deny that WP Curve started and gained initial traction exceptionally faster than most.
I disagree. Most founders with an audience can generally get 10 paying customers fairly quickly. And, frankly, I think 10 days isn't at all fast, especially these days.
And the impressive part of this story is its not 10 customers within 1 week of "launch" day. It's 10 customers within about a week of deciding on the "idea". Idea --> MVP launch --> Paying customers... 1 week.