Oh most of us will definitely care once linux developers start targeting the Ubuntus instead of the Trisquels (like how developers now target "android" instead of AOSP). I mean just look at how Gnome behaves now that it is the default DE.
A truly mainstream distro would be the death of the Linux desktop. I hope that year never comes.
As long as the code is libre, the Ubuntu LTS releases will perfectly map the Trisquel ones.
Today, if some service needs propietary code, it's doomed to rot.
For firmware with desktop users and programmers/devops using Ubuntu at work -not an issue on servers- , it's preferable to use the Xanmod kernel with Trisquel than falling into thw whole cascade of propietary code in Ubuntu.
At least nonfree firmware it's a non burnt hardware ROM; that setup it's 90% free according to the FSF values. Also, you don't get overlayed taxing crap as snaps.