Vincent
The main benefit of Flatpaks for me as a user, is that I can upgrade my system without fear of anything breaking (I use Silverblue, which relies heavily on Flatpak to enable this).
I think you should look at the runtimes basically as a repository. There are a bunch of libraries in there, and you make sure that your application works with those versions. Except that now, these libraries and versions are consistent across distributions, so you can support multiple distributions in one go. Additionally, it’s the application developer, who knows the application well, who ensures this compatibility, rather than a packager. Which, again, benefits me as a user, in that I can use the app even if my distro doesn’t have someone to package it.
From the post:
In some ways, this release might seem notable largely for what isn’t here. We’d planned to update the DNF package manager to a new, speedier version. We also hoped to showcase a long-awaited refresh to the user interface for Anaconda, our installation program. However, we decided these things just weren’t ready in time.
From the full report:
For the experiment, two panel providers helped us recruit 12,000 survey participants across Spain, Germany, and Poland.
So given that they used third-party providers, I don’t think they would have been biased to Firefox users specifically. (And in fact, given the current state of the market, the majority probably wasn’t a Firefox user.)