Mice in general are shockingly unproductive as compared to keyboards - using Gnome in a primarily keyboard-driven manner is where it really shines.
1. That I'm probably at least a proficient user (newbies tend to not keyboard)
2. That I'm probably on a non-mobile device with a large display.
If I'm not using the keyboard, but rather using the mouse, that indicates:
* I am absolutely not on a mobile device.
Absolutely none of these indications point towards mobile-ification of the UI. The only way G3's UI direction makes any sense is assuming touch input.