Like all Hue bulbs/lamps, The two companies only recommend using the hue go with a hue bridge. It’s technically possible to connect it without, but it can potentially disrupt your zigbee network because these devices tend to lose the messages they are asked to repeat by other Zigbee devices like sensors. This issue was verified by smartthings engineering. they don’t have this problem when connected to their own bridge. If you don’t intend to have any other zigbee devices, then that’s not an issue.
FAQ: Do I need the Hue Bridge/Hub to Use a Hue Bulb with SmartThings?