It allows to activate the ability even when there is no target for it, be it to just add loyalty counters onto the planeswalker and not waste a turn doing nothing, or to get an extra effect out of the ability that doesnt need the targeting part
Then exile it.) The creature is the source of the damage, not Nibelheim Aflame
Lord of Extinction In graveyard-heavy Commander games, Lord of Extinction often becomes massive enough to one-shot opponents
Knight in Sour Armor: A number of characters, particularly Wiegraf, share this trait
But then you can activate it for four mana to proliferate, so after your opponents' defenses have been set up and you cannot attack further you can do that a few times to finish them off
Nevertheless, Berserks restriction didnt stop the degenerate decks built around it from enjoying some success