> In other words not a meaningful barrier.

And yet many report it works, at least for now, and the excess load due to scraping activity falls precipitously when Anubis or similar solutions are used. Maybe once this sort of challenge is used almost everywhere we'll see concerted attempts to get around it, but for now it is easier for them to just move on to another target.

> a $5000 ASIC-based device can hash SHA256 at 200TH/s or more

Peanuts for the big players, but many (almost all?) running smaller scale scraping operations are going to find $5000 rather prohibitive, and they are unlikely to be able to integrate it as they are probably running a “stock” scraper that they didn't write themselves.