For someone to send me a message on signal, they have to either social engineer me into adding a number I don't know, or they have to steal a device from one of my existing contacts, get it unlocked, and send from it.
There is no way for them to go from knowing my phone number to me receiving and processing an untrusted image without them first somehow becoming a contact.
iMessage has no option to require friending first, before receiving unsolicited messages.
That doesn't seem like a "slightly easier" thing, but a rather significant difference.
For someone to send me a message on signal, they have to either social engineer me into adding a number I don't know, or they have to steal a device from one of my existing contacts, get it unlocked, and send from it.
There is no way for them to go from knowing my phone number to me receiving and processing an untrusted image without them first somehow becoming a contact.
iMessage has no option to require friending first, before receiving unsolicited messages.
That doesn't seem like a "slightly easier" thing, but a rather significant difference.