I'm afraid you're going to have to be explicit, because the idea of using Bcrypt for that reason makes perfect sense to me - the logic that makes Bcrypt better than SHA-256 for passwords seems to apply nicely to Bitcoin. Hardware optimization privileges the few who can invest in the hardware over the many who are able to run more commodity hardware, and is exactly contrary to the P2P Bitcoin ethos.

(A similar point applies to time-lock puzzles: http://www.gwern.net/Self-decrypting%20files Why were Rivest/Shamir/Wagner unhappy with brute-force decrypting? Because it's so amenable to hardware optimization. Why were subsequent researchers unhappy with successive squaring and looked for memory-bound hashes? Because squaring is still implementable in hardware.)