A Hardware Wallet's primary function is to store private and public keys needed to access Crypto like Bitcoin.  In other words, a hard wallet can be viewed like a storage vault.  A vault for Crypto addresses including public and private keys.  Above all, a hardware wallet should ensure isolation between your secrets and the internet.

In short, Hardware Wallets offer a convenient and affordable way to keep your Crypto and private keys safe while you are online.  They are easily backed up and your Bitcoin can be recovered in case your device is lost or damaged.

On the other hand, Software Wallets which include desktop, mobile phone and Web wallets are inherently insecure.  PC and Smartphone vulnerabilities are discovered daily and are well known to hackers.  Subsequently, when these vulnerabilities are exploited the result is access to your Crypto.  Because of this, it's just a matter of time before you lose your Bitcoin.

In conclusion, Hardware Wallets are the best option to protect Crypto from hackers that would otherwise steel them.