What’s the purpose of Hardware wallets?

My current setup, I've created a Private key offline. I have it stored in 2 different safe locations etched in metal. This Cost me about 4$. I keep 75% in cold storage, 15-20% Hot wallet, 5% on an exchange.

• If I used a Hardware wallet, Would I still need to back up the private key somewhere incase of the wallet failed?
• Am I trusting the manufacture to have not tampered with it, put in hardware spyware, or get corrupt in the future and push out bad firmware?
• What are the benefits from going from my setup, To a hardware wallet?

I am ignorant with hardware wallets, These are just some questioned I've had before I took the leap into a hardware wallet.