To a degree, I see the author's point. But there is a catch for me: I have a few older phones and the reason why I generally prefer Pi over an old phone is the OS. If I could get a full-fledged linux on a phone, I don't have a big reason to look at Pis: I don't need the gpio in almost all cases. For most phones however, this is not only not straightforward but in 99% of cases not possible at all.