The author talked about "productive use" - you listed gaming and browsing. In many circles those don't rank as productivity. There's a fine difference between "great"/"cool" and "being productive".
I know tons of CEOs who are more productive because of their tablets. The reason is that the form factor makes it easy to carry it everywhere. So they always have documents in Evernote, Dropbox, etc and are able to manipulate those if needed. Sometimes accessing information is the key to productivity.
Now, I am sure someone will want to debate the idea of CEOs being productive, but that is another thread.
You're espousing a pretty narrow view of what a computing device can be used for in a way that produces some value for its user.
I'm pretty sure every business prefers a 'narrow view' of what productivity means. The article is in relation to productivity.