Once you've downloaded and imported my public key, you can use it to verify software and binaries released by me.
You can also use the key to encrypt emails you send to me. In that case, I would also need your public key so I can encrypt the emails I send back to you. The excellent [Email Self-Defense Guide by the Free Software Foundation](https://emailselfdefense.fsf.org/){target="_blank"} describes how this process works.