Well for one it is really much much work, and actually a lot more legal fuss to accept payment for users and pay the authors. What I though was allowing authors to specify a single banner that would be shown on all 'comic view' pages. this way an artist gets something no matter which view the user is using. Also even in the comic view the site doesnt use up the bandwiidth of the original site, because the image gets cached on our server.
The prime reason why this site was created is because a lot of webcomic sites are slow, load up too much unneeded stuff (and I don't mean ads by this, I mean like fullscreen high definition backgrounds, user comments, header artwork etc). I don't have any issue with artists getting revenue for their work, what I wanted to do was a place that you can visit from any device and read your comics.