You give up reputability by using PGP/GPG, which is a pretty big deal when transmitting secrets, and in the default configuration that everyone has GPG involves

You give up reputability by using PGP/GPG, which is a pretty big deal when transmitting secrets, and in the default configuration that everyone has GPG involves using long-lived secret keys on untrusted devices. The first is a problem that is often not thought about in the moment. You know you need to transmit a secret, but it is rare that people think about under what future circumstances they will want to deny having sent it. The second is a practical defeat of the assumed security model. The GPG secret is a high-value target that is relatively easy to snag from unencrypted memory on untrustworthy devices.