From a practical point of view I advise against such system.
Dying is a failure, a punishment, a thing the player is to avoid. If it's a good thing then what is the punishment? Being healed and at a full health (but that can be fixed easily, by dying )? The thing is, an advantage must be something that is HARD to obtain, dying is trivial to obtain (enter the dragon's cave and do nothing).
I suggest to look at it from the point of view what could be the main punishment (instead of dying).
Note: I have seen one game where dying was good that worked, so it's doable but... it was not impressive.
Dying wouldn't be universally rewarded - it generally represents time wasted, or progress toward the end of the game lost and those would still be true even if there are benefits to dying. I agree that beneficial death could make a game way too easy if it were designed wrong; the player should not be able to gain more and more benefits from, for example, repeatedly completing the starter area and committing suicide. The proposed rewards of death aren't literally rewards for dying, they are actually rewards of what the player accomplished in life before dying; thus accomplishing the same thing again would not increase the reward, and the reward would mainly allow the player to avoid the grinding that was necessary to accomplish that goal the first time. My design goal isn't to give the player a reason to do boring things, and both too-easy play and repetition are boring things. I just think time is a dimension of life which has a lot of untapped potential for game-ification. And philosophically the idea of being able to re-live a life and perfect or evolve it is very interesting to me.