Given that said game is also for sale on the Humble Store, I find those statements dubious at best.

I don’t think that’s a fair assessment. Comparing to a traditional loop, it has marginally better thermals, one less set of tubing (i.e. places for leaks to spring up), and a smaller form factor. Wether or not those are “worth the money” is completely subjective. As someone interested in custom SSF builds I thought it was interesting.