I also tried TrueNAS scale once (but I think at the time it was quite new so maybe not how it is now) and didn’t like it either so I won’t speak about that.

If it were literally just for network storage and nothing else I guess the way to go might just be to hook up a usb drive to ones router (if it supports that). So most people probably do want slightly more or at least the option to expand capabilities without having to fundamentally change their setup.

But in general I would say that yes, the web interface is definitely part of the appeal. I think what something like Openmediavault offers is that someone else chooses sensible presets, it gives an easy to use gui that allows oneself to get stuff done without any major technical knowledge, and it also creates a community with a shared similar setup that can offer support.