Let's say I like a specific shade of green, and I copy paste it for different theme elements. But then I realize that the green should be a little darker. Now I'll have to copy paste the new hex into each element. If you give us the option to create a variable called for example myGreenColor, and then let us use myGreenColor as the color of certain elements, then I'll only need to make changes in the variable and they will automatically reflect on the widgets/elements.