I have it set so high because it can take time for the AI to receive a status update indicating that one of its allies health is below healing level and then a little more time to cast the spell. At the longer end of the response-time spectrum, it may only be a second or two but for a class that doesn’t have a lot of health to begin with, that can be life or death.
If the raven were previously healing the hellhound pet or another player ally in multiplayer, it could take a few seconds for it to finish the first heal and then turn and heal its master.
This early healing also helps in situations where the player is losing health faster than the raven can replenish it. In that case, starting early may allow the player to survive an extra couple seconds.
I’ve played healers in 3 MMOs, I figured I’d try to impart some good habits on the raven. 