The idea of 'Show HN' is for people to post projects that they've created themselves, regular submissions are people showing HN cool stuff other people have made.
Fun fact : I informed the author (which I'd a good fortune to get to know him for some time) this morning (east time zone) that his project is (again) on the front page on HN. He was in the air on his way to Taiwan. We both wished it doesn't break but it seems like it did and he restarted it again.
For me it was when I discovered React-Native. As a one man show in the beginning of our mobile application existence, developing both for Android and IOS at the same time was a blessing.