Yes, SDR is less efficient than a specially designed radio chip, but what you gain is flexibility. With SDR, your radio can use any transmission encoding, you are mainly just limited by your polling rate.
Specially designed radio chips thrive in constrained, high-volume manufactured devices. However, for development purposes, being able to use LoRa with an SDR is an amazing step up.
I like to think of the multiverse as an infinite field of colored static, and our universe is just a tiny segment that managed to represent a comprehensible world.