I get the comfort that "normal person" would send an SMS "it was me Greg, call me back" if you don't pick up and most of my family is on whatsapp anyway.

Scammers or spammers will never send an SMS with clarification that they wanted to call you.

But a normal person could be calling from a doctor's office, a hospital, or your child's school - and not an actual cellphone, and they may not want to text you (or not be allowed to text you) from their personal cellphone, either.

As a parent, the "block all numbers!" approach has always seemed incredibly naive to me.

Same as GP. I silence unknown callers, and unknown text messages. They can leave a voicemail, and I might check it at some point. I check unknown texts a little more often, but they don't interrupt me with an alert which is the important thing.

No police/fire/hospital emergency outcome is going to hinge upon someone else answering a phone call or text messsage.