Theres not even as many once-use flicker effects as you probably think
Its playable in UR decks with a lot of spells, but even 10-11 noncreatures wasnt enough to get this above 2-3 damage in practice
However, the last part of the ability will check how much life you've gained as the ability resolves, so if you've only gained 5 life this turn by the time the end step comes around, you could still gain 2 more life while this ability is on the stack in order to return the target creature card to the battlefield instead of your hand
It's already a 7/5 with trample and haste for six mana that gives you a free Jagged LightningJagged Lightning as a treat, but the lore continues to build after that
Then, Madam Mim can bounce him safely back into your hand, setting up a vicious cycle that, if it isn't stopped, can give you a huge lore lead