Why is it in the main page? It's a super well-known project no?

Because someone thought it was interesting, and enough other people upvoted it.

Just because you know about it doesn’t mean others can’t benefit from the mention.

https://xkcd.com/1053/

Looking at the comments it seems like there are still people not using it

It’s been posted many times, I think mostly due to it’s association to Mitchell Hashimoto. It’s left as an exercise the reader to determine why this is important.