I'm not sure what you mean by "gave up on SMS." What were they supposed to do with SMS (which is an outdated protocol anyways)? I get the small convenience of sending all your messages from one app (Signal), but I also understand the justification and wanting to prevent confusion about texting Signal-encrypted messages vs. SMS messages from the same app.

I can't speak to the whole blocking thing, but it sounds like an extremely unique, isolated instance.

You also have to open the gallery to send two pics instead of being able to select multiple.

Seems like a very minor UX issue that can be fixed and is not worth sending unencrypted messages for.

Also: Saying Signal "missed its shot" is very cynical and absolutist, which in turn can make people feel hopeless about getting their digital privacy back and taking back at lest some control of their lives, which doesn't exactly advance the values of the privacy community.