Customer interviews are pretty much worthless. People speak louder with their actions. That is why A/B testing is crucial to growth (hacking or not).
Anyhow, don't buy into the hype. Most of the growth hackers out there are social media gurus who discovered a new way to label themselves.
I didn't make my mind. That's why I wanted you to explain it. And I quite agree that growth hacking is very different from customer development. What I am saying, and you apparently is disagreeing, is that you first do customer development and only after product/market fit you do growth hacking. I am now only doing customer development and I think is not a good thing to already start growth hacking.
I am not "buying into the hype", on the contrary, I am postponing the growth hacking for me. I think you assume too much of what I think. But it is ok if we have two different concepts about what growth hacking is - even though I can't say i KNOW what it is.
Basically, I agree with these guys: http://jwegan.com/growth-hacking/autopsy-of-a-failed-growth-... and http://www.aginnt.com/post/46854446756/interview-a-growth-ha...
That's where my concepts come from. If you think that me saying "customer development" is BS and that I should be trying to grow like hell and not wasting time with delusional customers interviews, or something like that, please explain why.