What the purpose of a Napoleonic age soldier to wear a bear skin hat and shako?

To keep warm or protection? then why some of the bear skin hat so tall? And is the cuirass of the French Cuirassier really bullet Proof?What the purpose of a Napoleonic age soldier to wear a bear skin hat and shako?
The hats were for neither warmth nor protection. Their main purpose (like most of the rest of uniforms) was display. Some hats - certainly the bearskins - had some slight potential benefit in combat. They added to the apparent height of the soldiers wearing them, making them look taller and therefore perhaps more menacing when attacking with a bayonet charge. And the thick fur and skin of the bearskin offered some protection from a slash by a sword.





The cuirass was not bullet proof, but it would have been some protection against full penetration by musket balls, because they were made of relatively soft lead (not steel) and therefore had little penetrating power against hard objects. The curved surface of the cuirass would also allow some hits to glance off. And the cuirass offered good protection against a slashing cut from a cavalry sabre. Nevertheless, its main function was display.