The content of your emails is not as secure as you may think it is.
When you set up an email account on your computer (or tablet or phone) you have the opportunity to specify encrypted connections. The trouble is, email is a store and forward system. Unless you know every server your mail will traverse, you can’t know that it will be transmitted encrypted from server to server.
You are also subject to trusting the mail server administrator of each server it traverses, sometimes as many as 4 or 5. While the transmission from your machine to the first server may be encrypted, subsequent transmissions may not be. What is more, at each server it will be stored in plain text format. It is trivial for any mail server administrator to retain a copy of your emails. It is also trivial to scan plain text files looking for key words such as the word, “password”.
If you want what is in your email to be secure, what you need to do is encrypt the content, not just the connection.
One commonly used tool for this purpose is PGP. That stands for “pretty good protection”. Encryption is a huge subject, but there tools in the cPanel control panel to help you get this done. More information about PGP and this subject in general can be found HERE.
Having said all that, there is still 1 good reason to set up secure (encrypted) connections from your email client to your hosting server: passwords. Secure connections are established before your password is sent and that means it is sent encrypted and not as plain text.