The funny thing is, you go on to acknowledge that a phone call is psychologically more urgent than an email, and ponder how email might be extended to cover that use case...or maybe, the person was not at fault and was actually using the right tool for the job!
Until the FCC develops redevelops any sort of interest in dealing with scammers, my phone is basically useless for most of the world to speak to me.
If you're trying to reach me and are not on my list of approved callers, you can email me, or decide you didn't actually want to talk to me. (No, I don't use FB Messenger or related spyware, either.)
On the other hand, I apparently pay much more attention to email than you - I generally respond within about five minutes, assuming there's some reason.
IRC exists for a reason.
I found a house for myself and a friend in a similar way, reverse engineer mobile app from MLS, scrape all listings once a day to get new stuff as it hits the market and you can now be far more selective than the crappy search on the MLS site allows.
https://github.com/WilliamFCipriano/FreeSMS/blob/master/data...
https://martinfitzpatrick.name/list-of-email-to-sms-gateways...
Given the synchronous nature of a phone call, it seems like the perfect medium for this kind of alert. Similarly, SMS piggybacks off of the same network and therefore inherits some of the same properties.
Doesn't the asynchronous nature of an IM make it less urgent than a synchronous phone call?
Except when you are asleep.
And when it comes to immigration, you are happy to be woken up in the middle of the night by a phone call when it means the difference between failure and success.
I would argue that the fact that you find SMS/phone calls a more urgent alert is a fault with your phone/communication setup - and twilio is an interesting hack around that.
But there really should be an easy way to make just as much ruckus from a simple email, based on topic/sender filtering... (hm, maybe there's a nice side project for an app in there...).