iMesssage allows you to filter out bad actors -- but raw SMS (green text message) does not. I was getting a few SMS messages a day, each from a different phone number, likely with a service like TextNow.com
Signal's message requests is a major selling point for me.
I recently created a Signal account after having a bad experience in which someone used my phone number to harass me with SMS/calls (every time, from a different VOIP number). It's frustrating that, even in this era, there is no good way to filter out malicious actors from SMS/call.