Currently, you can turn on a light, set its brightness, its color, transition, etc with one service call to light.turn_on.
In contrast, climate.set_temperature can only do one thing at a time. If you want to set hvac_mode AND temperature, you have to call the service twice to set them separately.
set_temperature should be able to do more than one thing at a time because it’s quite common to set the temperature and the mode.
Can we add the fact that you also can’t add multiple entities in the same service call as a list either. This is true to climate.set_hvac_mode where you can’t change the mode to multiple entities at once.