Dwarves are not heroes?

[Pitchwife]

Originally Posted by Rumil

I think there may be a difference between a hero from a settled culture, who is in charge of, say, a unit of soldiers, like Eomer or Faramir, and Thorin's situation

True; I overlooked/neglected this part of your argument.

As for Bilbo being sent to explore on his own, I think his ability to move noiselessly was one of the reasons, the other being the fact that Smaug, who had never met a hobbit, wouldn't be able to identify his smell - these were the reasons why the Dwarves had agreed to hire him in the first place. (The magic ring proved rather handy, too, but I can't remember whether the Dwarves knew about it and its properties when they arrived at the Mountain.)

[Groin Redbeard]

Originally Posted by Pitchwife

(The magic ring proved rather handy, too, but I can't remember whether the Dwarves knew about it and its properties when they arrived at the Mountain.)

Bilbo told Thorin about the Ring when the Dwarves were trapped in the Elf King's dungeons. So they knew that Bilbo was silent, invisible, and unfamiliar to Smaug. Though I think it all comes down to duty. Bilbo was hired to be a burglar and was going to be paid handsomely for it.

As has been stated before, the Dwarves took the trouble to procure a signed contract with Bilbo in order for him to be paid, but this also insures that he does his job.