Curious if we are seeing any better news on this?
I would say it’s highly unlikely you’ll ever see any kind of native support for it. They’ve chosen Z-Wave, ZigBee and Bluetooth as their choice of radios through all three iterations of a ST ‘hub’.
Truly the only way you’d see this integration is if Lutron opened up their Caseta bridge so that ST could connect to it through the cloud. Local integration is almost guaranteed never to happen.