H&FJ is practically THE type foundry for original typefaces. They compete on quality rather than price or other tangible benefits. Unfortunately, it's been impossible to license H&FJ type for real web use until now.
The most likely group of people who will use this are type enthusiasts who prefer H&FJ type to the competition's. I can predict there are a lot of designers who will use this service for their personal or business sites.
As a competitive offering, though, this doesn't cut it. Buying individual fonts feels outdated to web font users, and the prices don't match up to Typekit (free with Adobe CC) or Monotype/Linotype ($10/month without a ridiculous 5 font cap).
H&FJ has chosen their business model, and they'd like to avoid the brand dilution of having poorly designed sites overusing their type. It's an interesting choice, and I hope it works out for them.