In a world in which anything 'weird' found on your chatlogs can potentially be used against you and the communities you are in on the media or even in court, I'd like to posit that it is important to not only have a secure personal computer and use encrypted services, but also ideally have those services be hosted by someone who can quickly delete all data associated with you.
Signal is neat because everything attached to you is only on your device, but ironically, this means that if you don't have access to your device before the people persecuting you get to it, then it isn't helpful to you.
On the other hand, if your Matrix admin finds out about your arrest and nukes the server, your persecutors are out of luck even if they manage to brute-force your laptop.
Food for thought.
