Dwarves are not heroes?

[Kent2010]

I came across this from Chapter 12 in The Hobbit...

..dwarves are not heroes, but calculating folk with a great idea of the value of money; some are tricky and treacherous and pretty bad lots;some are not, but are decent enough people like Thorin and Company if you don't expect to much.

This struck me as being almost completely contradictory to my image of dwarves in LOTR.

In The Council of Elrond Gloin tells the council how the dwarves rejected Sauron's bribe. They rejected wealth, safety, and even the dwarve rings Sauron possessed.

Also the dwarves of Erebor served as a stalwart against Sauron, protecting the West.

The dwarves seem to be a more selfish, and more greedy race, but unheroic? I am having trouble trying to reconcile the low image of dwarves in The Hobbit as being "tricky" and "treacherous," and what I think is a pretty noble image in LOTR. I guess it would help to try to figure out what Tolkien's definition of a "hero" is when he writes that dwarves are not heroes in The Hobbit?

Is Gimli not a hero? Gimli is the one that comes to mind, and someone might argue Gimli is an exception that dwarves in general, are tricky, greedy, and treacherous...but they can be "decent enough." What about King Dain?

But Dain Ironfoot was a worthy successor. And now we hear that he fell fighting before Erebor again, even while we fought here. I should call it a heavy loss, if it was not a wonder rather that in his great age he could still hield his axe as mightily as they say he did, standing over the body of King Brand before the Gate of Erebor until he darkness fell.
-Unfinished Tales, The Quest of Erebor