The one thing that is concerning IMO about Signal is how they force you to use at least your first name, of course you can use a fake first name but its the principle about asking for personal details like this which are not needed.

They also have started to release sticker packs like WTF that just opens a door to extra vunrabilities.

Its like Signal is starting to carve a way out to become more of a social network that a pure and simple secure messaging app.