[yellowarchangel]

You might have missed it in the article, but their explanation is really apt.

"Therefore, we thought that if we can get first paying users and MRR over the weekend and get back to YC next Monday morning, they would see that we had achieved MRR in only a few days. Additionally, we would look like a team who could move fast, listen to feedback and get stuff done."

The reason they were rejected is because they had no MRR. They were also told they need to move fast.

They proved over 1 weekend that they can get $500 in revenue and move fast.

It's the notion that they got feedback, moved fast to implement feedback, and showed that users were willing to pay on day 1 with a half-baked MRR plan.

Also their reply email hits all the points they were rejected: https://ghost-veed-blog.s3.eu-west-2.amazonaws.com/2019/06/S...

They did all this in 48 hours as 2 developers.