[bangboombang]

Exactly my first thought. I like Threema and one of the reasons I was an early adopter is that the founder worked on m0n0wall before, an OSS firewall that I used for a long time, in contrast to it being just some guy I never heard of. It made me accept the closed source nature. Another big factor was that I indeed consider Switzerland to be a more trustworthy/neutral party in general when it comes to global politics, but this obviously doesn't have to apply to every single individual in that country.

[_-___________-_]

Why use Threema when there are alternatives that are not closed-source? You had to begin to use Threema, which presumably carries the same difficulty as beginning to use something which isn't as questionable.

[mmPzf]

A big plus for me was the option of using it without mapping the user account to a phone number, something that e.g. Signal doesn't allow.

[bangboombang]

It was consensus between colleagues/friends. And because you still need to trust open source software as well. I certainly don't have the time to review the code, and the "somebody else will do a thorough code review" fallacy should be well known by know. As said, Threema at least had a name attached to it that I somewhat trust.

Telegram for example doesn't exactly tick the "not as questionable" box for me, not least because it isn't entirely open source either, but also because I always find it weird if someone is pouring money into software that is available for free, with no obvious benefit for them in return.