Why Is the Pool’s Main Wallet Typically Kept Offline in a “Cold Storage” System?

The pool's main wallet, which holds the majority of the block rewards and fee income, is kept in cold storage to minimize the risk of theft from a cyber attack. Cold storage means the private keys are generated and stored on a device that is never connected to the internet.

This makes it virtually impossible for hackers to remotely access the funds, protecting the pool's financial reserves from online security breaches.