Sorry Cartesianism in action :

If Napoleon's hat cost 400,000$, each man's hat cost 10$

Or do you mean that the hat was the best part of Napoleon ? That any french general appearing on battlefield with this hat "athwart", when most wore theirs "fore and aft", would be confused with Napoleon, boosting the morale ?

And now the historical question:

Do you have source of french general officers, other than Bonaparte, wearing hat "athwart", either in republican or imperial period ?