You can still communicate with your SMS-using friends via the normal means… IMO mixing totally secure and totally insecure communications in the same app (the same list view even!) was always a poor idea.
It seems to me like this improves OPSEC for very privacy focused Signal users, but increases the barrier to entry for "casual" users who may not care enough to use a separate app for certain people, but may be convinced to use Signal for SMS.
All that said, I'm not sure how any of that actually plays out in the real world, or if there were that many actual users doing just that.
I'm glad that dropping SMS means nothing to you. But "i don't see how you can known signal in anyway" for dropping a feature sounds disingenuous.