As the article describes in the end of its second chapter:

Sometimes an existing user would mention that they were happy to hear about us on their favorite show; sometimes a random person (not even in marketing) would remember us from an old podcast mention. Even if they didn’t convert at the time, they thought that Ahrefs was kind of cool—and this brand recognition stayed in the back of their mind.

That’s when it all clicked.

We were going about it all wrong—rather than being a tool for lead generation, podcast advertising is a tool for gaining exposure and brand awareness.

Sometimes converting a benefit gained from service, podcasts in this case, to monetary value is a simple matter of counting gained profit. But one has to remember that not everything can be measured in dollars, such as brand awareness. Doesn't help to pay the bills but I'd think of it more of a long term investment.

Without knowing performance of other channels, if I found something that I was fairly confident was delivering break-even ROAS on a 1yr value as a SaaS marketer, I'd do this all day.

There are so many opportunities to reduce churn, increase LTV, etc. that tipping the scales to make this channel profitable are probably pretty doable. The harder part of marketing is finding a channel with strong signal, and breakeven ROAS is absolutely strong signal.

Agreed. To me it sounded like the takeaway should have been "Don't sponsor podcasts, they're a terrible investment." Now, if you're a big enough company that you can afford to blow $50k on brand awareness, maybe that's okay. But for anyone smaller it sounds like there are probably better ways to get your message out.