One of the hurdles in helping people/clients with custom themes or plugins is that after uploading once a ZIP, there’s no easy easy to replace with newer versions. Setting up ftp is cumbersome for many and I will never admit I do edits with the Theme/plugin editor. Nope.
On another project outside my domains, a new WP site was set up with this plugin
that makes it easy for me to update theme/plugin code in an ftp-like interface.
I agree that WP Pusher is such the right way to go for Github hosted themes/plugins. I tried to “push” it for SPLOTs but not sure it gets much traction. I am planning on making that the suggested way of installing.
But I am thinking more of people doing some of their first work. Because WordPress does not allow uploads of updated themes/plugins, I suspect most people never update ones that are not in the WP.org repository. I doubt many people even have or know how to use FTP clients (I still use Fetch, the first one ever tried) and the setup is always non trivial for getting credentials. So this seemed a nice way for people to be able to do some level of minor uploads to a site. Maybe not.