The reasons that they highlight seem like they are correctly aimed at the people who could want to use it. This is the highlighted features:

- Lightweight Desktop Environment

- Intuitive Layout

- Completely Customizable

- Freely Available

- Portable

If you don't care about any of those things then yeah, Lumina is not for you.

The "features" page also features even more features that potential users could care about: https://lumina-desktop.org/features/

But again, if nothing there pique your interest, then Lumina is not for you and you're looking for Gnome, KDE or something else similar to those.