How did Sindri and Brokkr win the bet with Loki, when Mjölnir is clearly faulty?

Question

I understand that the brothers endured a lot of tough challenges, especially from Loki (who tried to disturb them in the form of a fly).

But still, Mjölnir is clearly faulty, which is supported by this quote from The Prose Edda, translated by Arthur Gilchrist Brodeur (1916):

Then he gave the hammer to Thor, and said that Thor might smite as hard as he desired, whatsoever might be before him, and the hammer would not fail; and if he threw it at anything, it would never miss, and never fly so far as not to return to his hand; and if be desired, he might keep it in his sark, it was so small; but indeed it was a flaw in the hammer that the fore-haft was somewhat short.

So, a bet is a bet, and when it is betted upon a head, it should/would be much more intolerant.

So, why and how did the brothers won the bet when the hammer is clearly faulty? On what criterion is the quality/bet gauged?

Answer 1

The bet didn't call for flawless creations; Sindri and Brokkr just had to do better than the sons of Ivaldi.

After that, Loki went to those dwarves who are called Ívaldi's Sons; and they made the hair, and Skídbladnir also, and the spear which became Odin's possession, and was called Gungnir. Then Loki wagered his head with the dwarf called Brokkr that Brokkr's brother Sindri could not make three other precious things equal in virtue to these.

_{Source: Skáldskaparmal, The Prose Edda of Snorri Sturlson, translated by Arthur Gilchrist Brodeur}

Apparently, the Aesir decided this was the case:

This was their decision: that the hammer was best of all the precious works, and in it there was the greatest defence against the Rime-Giants; and they gave sentence, that the dwarf should have his wager.