Reminds me of the mechanic where each time you kills or hits something, you gain health back in MMOs, MOBAs, FPSes, etc.
This leads to some interesting meta game. You go find trash mobs to beat up and heal before returning to the fight, much more item efficient. That means you never have to use items as long as you have trash mobs around.
I am not fan of this mechanic. I find it annoying as health pickup mechanic. You always have dudes camping around trash mobs or health pickup to abuse it to the max. It always devolves to who know how to heal most wins.
Of course, I know nothing about Bloodborne. I wonder how they will implement their take on this.