Every single business model including copywriting utilizes the concepts of "Marketing & Sales".
Human psychology, how to get their attention etc.
And that's what its all about.
But these business models are just VEHICLES to help a business scale through marketing & sales.
So the business model of a "Graphic Designer" is just a certain vehicle, that "utilizes" marketing & sales. (through vibrant colors in images & thumbnails, getting peoples attention)
But the business model of "Copywriting" is SOLELY about MARKETING & SALES.
Copywriting is not just a vehicle to UTILIZE marketing & sales, Copywriting is the DIRECT APPLICATION of marketing & sales.
Copywriting = Marketing & Sales (Just as a synonym)
Graphic Designer = "Using Concepts" of Marketing & Sales
Learning copywriting unlocks the ability to understand every single business on the planet, because you learn the art of marketing & sales.
And that happens in no other business model.