Privacy

Emails are encrypted in transit but they are not typically encrypted at the mailbox. As for Gpg I would avoid it as it has only uses a single key and if someone gets access to the key they can decrypt stored messages. This is very different than a lot of other encrypted messagers that rotate keys based on an algorithm like double ratchet with old keys being deleted. If you delete a message in a app like Signal there is a very high likely hood that a message can not be recovered even if you device gets compromised later and the adversary stores all data that goes over the internet.