What I hoped would come through was something like:

ROI for that spend was XYZ. LTV for user acquisition was ABC compared to Adwords/FB/print etc...

Is 129 signups good compared to other efforts? Are inbound leads from podcasts more engaged or higher likelihood to pay than other channels?

I'm not sure what the value here is, other than saying something like "don't spend advertising money in an ad channel if you're unfamiliar with the details of the ad channel"

My main takeaway: it’s not always all about measurable ROI.If you look in the right places, you’re likely to see some other kind of magic at work.

Sounds like good advice if you want to waste ad money, even considering the "half of all advertising money is wasted..." koan. At the end of the day this "magic" has to turn into measurable ROI.