It is the most important.
Owner Key/ Master Key can recover your account. It can be used to change the other keys. It's best to use the posting key when doing social actions like posting and commenting. Use the Master Key/ Owner Key sparingly. Store it offline somewhere just in-case you need to recover your account/ update your other keys.
Thank you @rentmoney I feel good hearing from you and learning a lot.
You're welcome.
Its always great hearing that our content is helping others.
Good luck on your Hive journey.