If (Audacity) used a self-hosted Matomo I’d be perfectly fine opting-in. 
Matomo, formally Piwiki, is meant to be a drop-in replacement for GA and even allows importing to make transitioning easier. It’s also under the GPLv3.
I understand that it’s a pretty complex piece of software that competes with large companies that have millions of dollars backing their products. Having a few usage metrics can be incredibly valuable for figuring out what’s actually used and how.
If they interpret the data correctly and correctly fill in the gaps for, likely advanced or GNU/Linux & *BSD, users who likely never opt-in, then it might become easier to use for newcomers and novices.