bread yeast is made to make bread. it will make any kind of bread. beer yeast is bred for an exact style of fermentation and so must be purer. this gives you consistent results. you don't pay for the yeast, you pay for the purity.
A question I came up with in my feeble little brain: since i am moving wort around while whirlpooling, would it be detrimental to run it through a chiller before returning it to the BK? oxidation shouldn't be a problem as I am not splashing, and i think I can put a fine enough screen on the...