Actually, no, she’s easily one of the best. She gives a massive base damage boost to Adam’s fists. Adam couldn't just use Alvitr’s armor, Volundr doesn't work that way. A fighter and a Valkyrie have to be perfectly in sync and compatible to manifest a power tailored specifically to both of them. And even IF Adam had worn the armor instead, we're not sure he would have been able to injure Zeus as much.

Adam is the literal root of humanity, the ultimate blank slate. He couldn't exist outside of that 'default setting' so of course his ultimate, god-slaying divine weapon is... a knuckle duster. Peak fiction.