Why does toilet tissue come on rolls and facial tissue come folded in boxes?

Here is the long answer: toilet tissue is stationary at the toilet in a specific spot and is a requirement (hard to substitute). People prefer to use different amounts and prefer to have available. Therefore the roll is convenient to keep it in place, to dispense as much as you need and to visually see how much you have left. The roll form factor works well for those requirements.
Facial tissue is usually a luxury item. You don’t really need them and they can be replaced with other types of tissue (kitchen towel, dinner napkin, etc.), a cloth, etc. The main benefit is that they are generally softer and more portable. That is why you see the container and boxes look nice… to be part of the decor in the house or packaged very small to be carried around. It is one of their main selling points. So the folded packaging form factor works well for those requirements.
I personally think that consumers are so used to the differences that it would be hard to change their habits unless there is a compelling reason.