It’s straightforward to use GPG via command line. I don’t find its CLI more complex than, say, SSH’s. I use it daily (with secret keys on a hardware key) for passwords, back up, file encryption, some email (admittedly most recipients don’t use encryption), software verification etc. Newer tools are simpler, but GPG is also workable.
For me the problem is that I use ssh way more often, so it’s easier to remember all the commands. I need to encrypt/decrypt something with GPG only a few times a year, and every time I struggle remembering the commands to do so.
gpg --help
provides an one line description of necessary commands. And ecrypt/decrypt is just `gpg --encrypt/decrypt`. You don't even have to specify an output file. Encrypt automatically creates a new file and decrypt outputs result in console so to put it new file a redirection is enough.