The confusion is around "storage" as in "offsite" versus "synchronised".

It's not the same as moving files around your disk, you can't just change the directory they are attached to, they have to be copied, and then it's optional if you delete them.

Your use case is not the one that relates to the expression "sync".

Also, is there really any reason why you don't just do it with a USB disk?

And the command line is the simplest way to do it. The GUI is designed for people with high time preference, to put it succinctly. Computer programmers and administrators have naturally lower time preference.