One of the things that libadwaita brings to the table that could have never been done without it in GNOME is accent color customization (that isn’t going to make it into 42, but maybe in 43 or 44), just like elementaryOS does with Pantheon; and the app itself can be recolored in many ways with some of the new features (like it already does with Metadata Cleaner).
It’s not a lot of customization in the hands of the users, but it brings loads of possibilites for the app developers themselves and guarantees that their apps won’t look broken due to some poorly implemented theme like it used to do with GTK3.
One of the things that libadwaita brings to the table that could have never been done without it in GNOME is accent color customization (that isn’t going to make it into 42, but maybe in 43 or 44), just like elementaryOS does with Pantheon; and the app itself can be recolored in many ways with some of the new features (like it already does with Metadata Cleaner).
It’s not a lot of customization in the hands of the users, but it brings loads of possibilites for the app developers themselves and guarantees that their apps won’t look broken due to some poorly implemented theme like it used to do with GTK3.
Couldn’t this always be done by the developer using their own CSS via GtkCssProvider?