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.