At the present time SmartThings brand devices are not compatible with HomeKit. They do not include the special HomeKit chip. When connected to the smartthings hub they can be used with echo or google home for voice control.
Any device which is compatible with HomeKit will have the Homekit seal on the box.
The IHome plug-in pocket socket can work with both SmartThings and HomeKit, as can the Lutron plug ins if you also have the Lutron SmartBridge, but I think those two are the only pocket sockets that do at this time.
https://support.smartthings.com/hc/en-us/articles/211523263-iHome-SmartPlug
https://support.smartthings.com/hc/en-us/articles/115000864766-How-to-connect-Lutron-Caséta-devices
As you noted, the Phillips hue bridge can work with both SmartThings and HomeKit. So can the Lutron SmartBridge.
The SmartThings brand pocket sockets cannot work with the hue bridge directly.
More discussion in the following thread: