The Internet is impractical for real-time transmission of audio and video. Text does not immediately grab an audience raised on television.
Images fill the gap.
Web readers come for pictures and stay if the writing is good. Images on the Web can look better than on a magazine page. Photographic prints have a contrast range of about 100 to 1. It is simply not possible to make one sheet of paper that has reflective properties more varied than this. Magazine pages are generally even worse than photographic prints in this regard.