The reason connecting through the Hue bridge is the officially recommended way is that Phillips did not originally provide anyway to factory reset an individual bulb once it had been connected to a zigbee controller. It wasn’t even easy to move bulbs to a new bridge. (Most zigbee bulbs can be individually reset with a blink pattern, but hues cannot.)
Consequently, adding bulbs directly to the smart things hub without using a Hue bridge meant that it was often very difficult to take those bulbs off the bridg even just to move bulbs to a new bridge.
There was an additional wrinkle because the Hue bridge uses the ZLL (zigbee light link) profile and the smartthings hub uses the ZHA (zigbeE home automation) profile. ZHA has more channels than ZLL, and if you linked a bulb directly to the Hub it was possible that you might be putting the bulb onto a channel where other ZLL devices would never be able to find it.
Consequently, adding bulbs directly to the smartthings hub without using a Hue bridge meant that it was often very difficult to take those bulbs off the hub later.
However, since that advice, there are now several ways to reset an individual bulb. The easiest is probably with the $30 Lutron connected bulb remote, which can reset an individual bulb on any Zigbee channel. So now you don’t run the risk of the bulb being locked to the smart things hub forever. But still requires buying an extra $30 device just for the purpose of resetting, smartthings doesn’t want to make that their recommended method.
As far as color goes, smartthings is able to adjust color on a number of different devices, such as the fibaro RGBW controller, Zwave RGB bulb, and a hue color bulb.
Maybe @smart can post a screenshot of his mobile app showing the device tile. He has a lot of colors hues. I only have the white ones.