The Only time a seed phrase is needed is when you decide to recover a wallet, and you never need to enter your seed phrase on your computer, only on the hardware wallet itself! The hardware wallet software running on your computer will never ask for the seed phrase to be typed on the computer. You also need to keep a secure copy of your seed phrase offsite, so if your house or apartment burns down, you can still recover. You may also want to give a copy to a loved one, for backup and estate planning reasons. Remember once you give the seed to someone they have the ability to access all of your funds and must keep it safe as well.