The “can support smartthings” is reliant on someone creating an integration - there is not currently one available. I have also ordered one.
Given that it uses the same ESP8266 as the Sonoff Basic, it should be quite straightforward to edit the firmware at [RELEASE] Sonoff, Sonoff TH, S20, Dual, 4CH, POW, & Touch Device Handler & SmartApp ($5 & $10 Smart Switches) with the correct GPIO pins for the Shelly? GPIO4 = relay control, GPIO5 = switch.