For me I won't recommend it because of the horrible lack of options when you replace your phone (let alone lose it). No encrypted migrate. No backup options. Unencrypted loses content (images).
I guess these are all features. For example, how are you going to do a backup that restores when you lose the phone (and thus the private key)? In practice, you would encrypt the backup with a passphrase, and the user would choose "123".
Signal aims to be the most usable secure messenger, not the most usable messenger that also happens to be secure.
Plus there's no way to search old messages.