You cannot read a digital prog in the bath.
You cannot read a digital prog on the bog.*
You cannot read a digital prog on the steps in the back garden whilst you are having a fag.*
You cannot read a digital prog when your kids have the laptop.
You cannot read a digital prog when your kids have the laptop, and the other Mac.
You cannot admire your collection of digital progs on your book shelf.
You cannot admire your graphic novel collection if they are digital.
You cannot read a screen for long, zoom in look closer, admire the colours, trace over, cut out, paste onto your bedroom wall, cover your school books with a digital prog.
You cannot have the same feeling as you do hen you get the prog in the post on a Monday morning and you savour it for later when the kids go to bed and you snuggle down for an escape for half an hour.
You cannot replicate the excitement of turning the cover and delving into the Nerve Centre, without trying your hardest not to peak at the first page of Dredd until you have read Tharg's message.
Now some might argue that yes you can print them out - but the will be low res, depends on the quality of your printer, and it will be on shitty paper unless you are willing to fork out a small fortune for high quality silk or gloss and then that will be more than buying the prog.
I wouldn't mind reading the prog online, but it wouldn't be the same, there's no intrinsic value, you don't feel like you are getting something. You cannot just come back to it when you want, pick it up for five minutes whilst you are waiting for your pasta to boil, or your train to arrive, or you just find five minutes need killing before you have to do something else - instead you'd have to switch on your computer, login, load up and find the page - it all seems so alien.