Because they'll do well enough for those interesting in having fun with their guitar, playing for some friends, and having something to build on. Few will ever take the time to truly dig into mastering both sheet and tab notations, learning the myriad techniques, and learning to more complicated parts of music theory - and that's okay.
They don't have to. In fact, for most people, I'd not even suggest they do.
This article is aimed at the person with the guitar in the corner that isn't ever really going to put that much effort in. And, again, that's okay. They don't have to. Sometimes having fun is the best goal.
Most of my articles are written for more advanced players and people who want to earn a living with their musicianship. This one? Not so much.
Why do you recommend this?
E:
I get this, but is seems against my impression of your hints. Is it to keep interest?
My first teacher taught by ear. "What do you want to learn next week?" "Ziggy Stardust." "I'll give it a listen and we'll begin on Monday."
As a lefty it was easier to first learn through sound and later hone technique (teacher was a righty).
Learning guitar is like exposing yourself to a spoken language. A combination of immersion and direct interdiction/correction (finger placement) worked for me.