The web server needs access to the key to sign the reply so the key is accessed all the time. With automation LE style one typically creates an account with LE

The web server needs access to the key to sign the reply so the key is accessed all the time. With automation LE style one typically creates an account with LE when one renews the key so there is no need to have an account password or similar which decreases the attack surface compared with any manual procedure. So while I agree that Google and friends have too much power, in this case the decision was reasonable.