One cluster of my friend base has entirely switched to Telegram.
Now I know I will get hit with a barrage of information why Telegram is also bad and blah but honestly at least it's a bit less info for the POS company Facebook.
threema is not open source and it is not free, Signal (better some European fork) without recent baggage would be better option
user base is extremely slow, in Slovak media Threema is associated with mafia and murder of journalist, it will be hard to convince people to use same app as mobsters
People also use money, mobsters do too. They breathe air, mobsters do too. I don't think mobsters using something that is otherwise legal to use is going to stop adoption.
The parent did not say it is a mafia app. But it's use really is strongly associated with mafia in Slovakia. That for sure will never make it very popular choice for people in Slovakia don't you think?
You can look for yourself, the only thing which pops-up on google when you search for threema and slovakia are the murders and mafia dealings with government officials and lawyers.
BTW the Threema encryption was not broken. The messages were extracted from an unlocked iPhone X of the main mafia operative (Kočner).
Slovakia is not exactly the largest country in the world and to extrapolate from 'Slovakian mobsters have used it' to 'this app is associated with the mob' is a bit of a stretch.
It may only be hard to convince non-mob Slovakians to use it, but that's a relatively insignificant number of people on the larger world stage.
if you hear money, mafia/murder are not the first words which come to your mind
if you hear Threema in Slovaka - mafia and murder are first words which isntantly come to your mind, because nobody else use this app, everyone is already on Whatsapp, Messenger or Viber and nobody ever heard about Threema besides few nerds until media started to publish transcriptions of Threema chats from mafia where they are ordering murder of journalist
you can downvote all you want, that's reality, same as when you hear Ford Pinto
In Germany, you usually hear about Threema as the app that you should use if you care about data protection. Signal isn't as well known, but it's gaining traction. Neither currently has even the slightest connection to mobsters, as far as I'm aware.