Privacy

I think their logic makes sense though. Signal as an SMS app is functionally pointless. If you can't convince someone to use signal because they are just using SMS anyway, then what is the point? If you are prostletyzing encrypted communication to people, an important aspect is communicating the why's. I think sms on the platform ultimately did do more harm than good, it confused the normal people, and presented risks for leaking data, since it was not always clear if hitting the send button would result in an encrypted message or not.

A nice example that is always brought up with signal, is matrix, which perfectly demonstrates the issue at hand. Matrix, which is touted as a 'secure' platform, is actually the opposite, it requires positive action to enable and maintain encrypted messaging, and because it allows insecure communication, it opens up tons of holes, either from user error or unclear messaging from the platform. (Things like severe metadata leakage and unclear communication as to what is encrypted or not). There is a reason governments and militaries around the world use signal over other options.

I think you only need to look at the recent Atlantic leaks to demonstrate that users don't actually know best as well. You have a general user base that has poor security hygiene and the concept of op sec is completely foreign. Confidential group chats would be constantly compromised by one person losing a data connection resulting in the message being sent as SMS and if you don't have automatic fail over, then SMS support offers no functional benefit, and only serves to add a workload that accomplishes nothing.

Signal has cultivated a platform that has no unclear boundaries. If you send a message on signal, it is e2e encrypted every single time, there is no scenario where this is not the case. That's more valuable than presenting the option to have an encrypted conversation.

I also don't really think that is a valid argument, none of signal's contemporaries offered this feature and it didn't stop them. I have never heard someone say that they can't get people to use Messenger, Whatsapp, or Telegram because it doesn't support SMS.

Another counter point is that signal's user base has only grown since they removed the SMS feature.

Finally, I don't think that what you are saying aligns with the previous comment anyway, in fact it seems like it was agreeing with me. The decision wasn't done because of developer resources, it was a conscious decision they made because they believed that SMS should not be part of their product.