Your seed phrase is what that you can use to access your bitcoin on your wallet and to spend the coin. Many people are sending email that they should enter their seed phrase on a site. If they enter the seed phrase their, the bitcoin will be sent to another bitcoin address by the scammer.
Do not backup your seed phrase online because scammers can get to it online.
And seed phrase is one of the most important components of the wallet and without you won't have access to your wallet so if anyone Is opening any wallet they have to put in consideration the fact that they have to keep there seed phrase safe because the moment they lose that is the end there is no way that they will get it back so once beaten twice shy but sometimes people need to learn the hard way.
And people also have the habit of keep there seed phrase online when they know own that it can be hacked so they need to find a more suitable way to keep there seed phrase safe. There better ways that they can backup there seed phrase instead of saving it online.