Correct. The original Xioami line uses their own proprietary encoding and will only work with their own controllers. Cannot be used with SmartThings. Same issue as the original iris line or the original NYCE line.
Whenever you see Zigbee devices, remember that SmartThings uses the Zigbee home automation profile (ZHA 1.2. ) It will also work with the special light bulb profile, Zigbee Light Link (ZLL).
But that’s it. SmartThings won’t work with other profiles like “zigbee pro”, “zigbee green energy”, “zigbee medical”, or any company proprietary versions.
So check for the certification description before purchasing anything.