FYI - thread from yesterday around the docs and concept: https://news.ycombinator.com/item?id=19610830 This appears to be the accompanying blog post. So, not a dupe and explains the higher level goal here. The post from yesterday, was before the product was actually publicly released, if that gives more context as to why this is new news.
FYI - I just posted a review video where I walk through Cloud Run doing some demos. Check it out at: https://sysadmincasts.com/episodes/69-cloud-run-with-knative