As I've said before; that was not their choice. The use of the clone army was decided by the Senate - the Jedi did not have a say. That the Jedi were expected to lead, or at least fight alongside whatever army the Republic had is why they end up leading and fighting alongside the clones, on behalf of the Republic. So, we end up with a couple of questions. Do you honestly believe that had the Jedi refused to lead the clone army that the clone army would not have been used by the Republic? If so how do you figure that would transpire? If, as I see it, the clone army would have been used anyway then how would the Jedi refusing to lead (and fight alongside) them be in any way a benefit to that army; to those men? I don't know how anyone can think that the Jedi chose to use the clone army when there are a number of scenes specifically pointing to the Senate deciding that.