All diffs given against the $31.38/3yr wholesale price from Verisign+ICAAN.
Not sure how that qualifies as "outrageously expensive".
You can make your own trade-offs, but for something that's literally the foundation of my online identity, business, etc I'm willing to pay $3.50/yr over wholesale for a company with a reputation, support, and generally aligned incentives.
You may choose to instead tie your online identity and business to someone charging less than cost to save half the price of a big mac a year. But I will find it hard to dig up much sympathy when we all find out _how_ they're planning to make money doing that.
You can use any registrar with R53, so it's more like:
if you really need to have domain registration written in Terraform and the other registrar doesn't provide it