I tested this passive and potions are not affected - however this should do with the new patch 1.05 (update: "healing globes bonus also affect potions", because potions were too weak for high health). But it doesn't. Either you forgot to do it for this passive specifically... ? Or it works differently than boni on items, so it is bugged.
Without fix no use - where it could have been used is hardcore where you actually have like 80-100k life. Thanks for fixing in the future.