A computer illustration doesn’t even exist. It is virtual. Nothing to sell (except a product). You can print them out but even then it comes from a machine and not a block.
And there are thousands of filters that each can make your photo “into” arty art. Random button pushing until you are satisfied.
Don’t belittle people who know how to handle a pencil or ink brush. “Wellll, that’s merely commercial illustration. There’s NOTHING to it.”
Even old storefront signs from hundreds of years ago hang in museums.
Hell of a lot more mental and physical accomplishment to create a drawing from nothing than to come up with a “credible” computer illustration.
https://www6.lunapic.com/editor/
Recognizing the difference between fine art and illustration is not belittlling. There is a lot of work in both genres that is horrible; and a lot that is uplifting, intriguing and/or illuminating—same as poetry. Good poetry is timeless; bad poetry is a waste of space.
But as to the economic value of illustration vs fine art, that is not determined only by taste and subject matter, but also by their respective marketplaces, which operate quite differently from one another.