Yeelight Smart Bulbs white temperature in app

Using my new Mi Desk Lamp I noticed that in Xiaomi Home it’s possible to set a specific temperature. Moving the cursor on a specific white in the high left corner the white temperature appears. It doesn’t happen instead when I set white temperature on Yeelihh Smart Bulb, also in the Yeelight app. I think it should be useful and interesting to know the exact temperature set.

Rather, I don’t understand why it is implemented on the Desk Lamp and not on the SmartBulbs.