Hi, author of the page here. I didn't expect this to end up so high on HN.
You're right that there is a place for free plans, the article I wrote is probably too one-sided. I planned on adding an extra section near the end for some cases when a free plan does make sense (I will wait until it is no longer discussed here).
Other than the "influencer" angle you mentioned, it also makes sense for products where you can offer the first X units for free, and many will have the desire for more (2 free designs for a website builder, or the first 10 levels free in a video game).