People were requesting the dome light to be able to switch between multiple HDRIs for lighting situations.
I think it would be cool if, the same way that in Render Setup/Scene Environment you can choose "Use Corona" there could be, right there, the option of adding many of those slots (like with 3DS Max's multi subobject material you can choose how many materials you want). So "Use Corona" would be one of many.
Ideally you could name the slot yourself.
Having that round check box would let you switch from one environment to another without ever having 2 at the same time.