why is it the norm in the manga/comic industry for comics to be done on paper rather than on digital formats?

I am in debate with my work comrades in this matter. I use a wacom cintiq graphics tablet and one friend in particular works on paper. We’re thinking of making a comic and stumbled upon this subject. Why is it that in the industry comics are initially done on paper rather than on a graphics tablet or such.

Thanks for reading my query and many more thanks for any feedback.