Why do sugar refineries cook the sugar canes they process?

Why is the sweet edible part of sugar canes (Xylem?) cooked when sugar refineries receive it?

That natural edible part is quite sweet on its own and can be eaten raw. In South East Asia, it's common to meet vendors who sell whole sugar cane juice in any market which tends to be very cheap (0.46 USD for about 350 ml) and can also be eaten in crystal form with all the dietary fiber, vitamins. etc.

What is the main reason for cooking it into "jaggery" chunks, which reduces its dietary fiber and vitamin content?