

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.

Idk about the lack of repairability, those things are really easy and cheap to fix in my experience. They are at least no less repairable than 95% of laptops on the market.