Private keys and seed phrases matters because they prove you're the true owner of your crypto wallet and funds. Without them you can't access your wallet. It's your responsibility to keep them safe, because you have the full control over them. If you lose your private key and seed phrase and someone else gets access to them, it can lead to permanent loss of your funds. Both should be stored privately, and you shouldn't reveal this information to parents, friends, or anyone else for the safety of your assets, because they might unintentionally or intentionally expose or misuse your security, which may put your assets at risk. To protect your assets, it's crucial to keep this information confidential and secure them at all times.
Yes Private keys and seed phrases are most important part of owning crypto. They are our proof that we own our digital money and without them we can not get to our funds. Due to this people in crypto world say Not your keys not your coins because we risk losing our money if we let someone else hold it. To keep our investments safe we must keep this information private and not share it with anyone not even friends or family. Storing them securely and offline is best way to protect our assets from being stolen.