What do you mean by “false sense of security”? Signal’s cryptography is pretty solid. It’s one of the only messengers with such a lack of metadata leakage; if you combine it with Tor you can add enough noise to the network-layer metadata to be more private than almost any alternative.
Don’t get me wrong, I dislike it on the grounds of being a closed platform, but few alternatives exist that support both offline messaging and have such little metadata leakage. I’m willing to hear suggested alternatives that do not bake a “cryptographically-secure, decentralized pyramid scheme” (cryptocurrency) into the protocol. I’m not aware of any such alternative at the moment.