Comment 5 for bug 1746310

Gunnar, Kubuntu and Lubuntu Next are free to install fonts-symbola if they want. (But they should really talk to Qt about getting color emoji support working everywhere too!)

The benefit of installing Noto Color Emoji by default is so that color emoji will work out of the box with any GTK+ app (with a few exceptions like Chromium, Firefox and LibreOffice). Color Emoji is advertised as an Ubuntu 18.04 LTS feature.

The benefit of not installing Symbola by default is that it's unneeded.