@sil wrote a nice piece talking about collecting machine data in Ubuntu: https://kryogenix.org/days/2018/02/20/collecting-user-data-while-protecting-user-privacy/
I have a very simple take from the perspective of previously helping make releases of Xubuntu. Without knowing who the users are yet getting machine date will allow targeting resources to the most common platforms and usage scenarios. We don't know what is "average" for an Ubuntu user in terms of hardware. Greater privacy is nice but developers need to know what they're building for.