Well, if you do that, then the cPanel services can be accessed non-securely.
If Non-SSL redirect destination is set to Hostname, then http://example.tld/cpanel is just going to redirect to http://server.hostname.tld:2082. And if port 2082 is firewalled off, then this connection will fail.
How I patched this for my needs, I created a new redirect script in cgi-sys to automatically redirect to the server's hostname for each service. Then created new ScriptAliasMatch directives in Apache before cPanel's ScriptAliasMatch's to intercept this and force a redirect to these custom cgi-sys redirects.
This seems to work for my purposes, which doesn't appear to be a major issue for most other people.
I really just liked the old way cPanel did this, when this feature was called "Always redirect to SSL/TLS". Using SNI for the cPanel service ports always seemed to be an unnecessary extra step. Since HTTP supports redirection (unlike IMAP, POP, and SMTP) going to http://example.tld/cpanel could always redirect to an appropriately secured URL (like a server's hostname).