This should be two different questions. Since I know little about the Swiss government just answering generally:
Should <public entity> ditch Twitter?
Unambiguously, objectively yes. Twitter’s reputation as a “public square” is gone, and it cannot now be relied upon to disseminate information. If I’ve already used my limited API calls a day scrolling through my feed for like an hour, I now can’t see official government informational postings? Not to mention the absurdly common outages now, the ridiculous content policies, the fake blue check system, and all the other stupidity that Musk has shoved into the system.
Really we shouldn’t ever have been using any privately held system for this (because such mishandling of the service was always a possibility), but Elon’s change have made it objectively unworkable for that purpose even on its best day.
Should <public entity> ditch it for Mastadon/etc?
This is a harder question to answer easily, but I still think yes. The argument against it is that a relatively tiny fraction of people use Mastadon still, and public entities do need to be where the public can see it. The counter argument for that is that people who don’t use Mastadon now can still click a link and open a website to view a Mastadon feed, and no one needs any more knowledge about what Mastadon is to view that feed. And then people who DO know Mastadon can follow those accounts, toot replies, etc.
Some people don’t like when it’s too quiet. For some it’s uneasy, for some it makes it too hard to stop your mind from wandering. That can make it hard to sleep or hard to focus on a task. White noise is noise that makes it not quiet, but isn’t so loud or too full of meaning to be a distraction on its own. Most people use something like ocean waves, running water, rain, wind noises, the warp core noise from Star Trek, etc.