Yes, there are hundreds of millions of professionals who need a computer for their work, while not being techies. They write and publish, do spreadsheets, edit photos and videos, make music, make invoices, read and send e-mails and so on.
It's like asking why a non-mechanic would ever need to use a car.
I did mention IT at offices buying computers for their coworkers. :-)
I know more and more people who are editing photos and videos on their phone/tablet - not movie producers, sure. But lots of YouTubers, influencers, etc.
Yes, but outside of corporate settings (Windows), there are hundreds of millions of people who work professionally with computers without being techies.
It's like asking why a non-mechanic would ever need to use a car.