Why would you do that?

Because, out of the miniscule market segment of geeks and techs, the tablet fills much of the requirements that people were purchasing laptops for 8 year ago.

Curious, not to be rude, why wouldn't you do that?

The tablet, as we see it today, really wasn't even a thing back when this article was written. Certainly not in the way that it is today. It's been a while since I've been in a 2004 mindset; but, if we consider a tablet as a 'large (as in not phone), mobile computer', then tablets certainly fit the bill. If we're thinking of a laptop as mostly a consumption device, then it still fits the bill. Even now, with the Tablet PCs that are now coming out; as well as all the productivity software that exists on the various tablets (including ssh clients), tablets are continuing to fill the place that laptops used to.