Copywriting and writing are the same. There are different types of copywriting, or writing, but they're all about putting words on the page. Words that will be read by others.
The most profitable businesses are fantastic communicators. This works all the way down from the likes of Apple to the local plumber who's always got a six month waiting list. But no business is a perfect communicator and many make serious mistakes which are losing them hundreds or thousands of pounds a day in lost sales.