There's a myriad of resources out there for learning a musical instrument. And an increasingly larger portion of which is free. So why take private lessons?
It mostly depends on the student and how best they learn, but regardless of your preferred method there's still no substitute for having a person there with you to correct your mistakes and inspire your progress. I book lessons one month at a time, so even if you only need a short series to get you started I cater to that style.
For the same reason, I don't teach from a method book, nor do I prescribe a specific practice regimen. Rather, I tailor my instruction to you, wherein I work as many of the tunes you want to learn as possible.
Playing what you want to play...why do anything else?