Slightly different way of doing things, though. The SMS payload is one way, the control structure is two way. USSD has two way payload space. The difference is SMS BALANCE to 450, wait 5 seconds, receive a SMS text back with the information. Dial *#100# and the balance appears immediately and is displayed on screen, not saved.
There are already, and have been for ages, GPS trackers that send a SMS with their location information. There aren't any, that I know of, that use USSD to do that. I think this is a promising technology. Not sure how long it will last given the roll out of consumer led 3G/4G/5G etc.