From my limited perspective, you don't have much draw unless you have a bunch of enchantments on board to trigger one of your burst draw effects
Itll function a little like an extra copy of Birgi, netting you bonus mana to just keep pushing that little bit more
This means that a creature may have to regenerate twice to survive the combat, once from damage and once again at end of combat
The worst-case scenario of some mom buying this for their kid at Walmart, the kid opening it, not understanding what it is, and it getting lost at the bottom of the toybox (cue "and some things that should not have been forgotten were lost") is not that outlandish
Neheb, the Eternal Neheb, the Eternal doesnt have a damage dealing ability to double, but it benefits from Mjlnir nonetheless: dealing damage counts as life loss and Neheb often gets into the red zone to make mana