Snaps are centralized, provided by one company. Sorry, but no. It can be 'better' for some reasons, but free software should not be limited to one or few app stores.
We can analyse if flatpack are security nightmare, but what are alternatives? That was my line of thinking. Complaining without comparing to other solution may not be honest.
The article is not critical of Flatpack, it is an endorsement of Flatpack.