system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel Comics] Why does Thor wield a magical hammer that grants people the power of Thor?

Given that he is, in fact, Thor, and therefore already has the power of Thor.

IIRC, Beta Ray Bill fought Thor a time or two and they were pretty evenly matched. They were roughly equals in power. Things happened, and as a reward Odin gifted Bill with.... a magical hammer that grants him the power of Thor! 

Why? They're already that strong. Why not find a weaker being who is worthy and give them the powerful weapon so that there are actually more worthy Thor-tier beings in the universe? Sometimes Mjolnir seems to have a variety of additional abilities, but why not tack on a different enchantment instead of one that grants Thor the power that he already has?
gpt
Actually, that's happened to Thor repeatedly. He's been banished to Earth multiple times and forced to adopt a human identity until he proved his worth.

Most recently, he was forced to live on Earth as a disabled man named Don Blake. It was meant to be the ultimate test of his worthiness; in this form he was not big or strong or powerful, and couldn't rest on those laurels by fighting monsters- however, as Don he proved he was still heroic by devoting his life to becoming a physician and healer of the sick.

This confirmed that he was truly worthy of his role as prince of Asgard, and so the hand of fate guided him to Norway where he recovered Mjolnir once more. But it's implied that if some other worthy had found it, they would have taken Thor's place in the cosmos.