Combine with heuristics like in the article, so you can crank up the difficulty only for likely bot traffic, and you've got a bot supported site.
That's not true. The goal is to raise the cost for bulk scrapers to the extent possible while minimizing any inconvenience to regular users. It's not about being slow for bots but rather reducing the asymmetry of the problem (from the perspective of the server) by imposing a (minor) cost on anyone requesting a page.
I know having the Anubis javascript at all gets in the way of some bots. But is the calculation helping enough?
Opportunity costs are real.