There is a discussion about that on the security stackexchange (https://security.stackexchange.com/questions/133239/what-is-the-specific-reason-to-prefer-bcrypt

There is a discussion about that on the security stackexchange (https://security.stackexchange.com/questions/133239/what-is-the-specific-reason-to-prefer-bcrypt-or-pbkdf2-over-sha256-crypt-in-pass https://security.stackexchange.com/questions/133239/what-is-...). The TLDR: > SHA-2 family of hashes was designed to be fast. BCrypt was designed to be slow. Slow == harder to brute-force == more secure.