Ask HN: Is "Data-Driven Growth" a Myth or Reality?

Every growth playbook preaches ‘data-driven decisions,’ and many successful founders credit being data-driven for their growth.

But how real is it in practice? Does it truly drive growth, or is it harder than it seems to collect, interpret, and act on the right data?

I’m curious—has being data-driven worked for you, or have you seen diminishing returns? I’d love to hear how the Hacker News community approaches this.