It's the age-old argument. I started out doing "folkie" stuff, strumming chords and throwing in an occasional "bass run". Gradually working from tab and finally breaking down to learn some chord theory, scales, and all that.
Many very successful players haven't a ounce of theory, of course, and some well-known guitarists tailor their reply to the audience.
Glen Campbell, at his peak, was on the Tonight show. When asked if he read music, he came up with the corny old line, "not enough to hurt my playing".
But interviewed in Guitar Player, he said that he practiced reading from clarinet books and such.
(BTW-Guitar Player is a fine rag, and full of useful items each month)
The problem most beginners have with all that theory and memorizing of scales and intervals and modes and all that is that it tends to be intensly BORING.
Running scales is great for dexterity and even ear training, but after a while...
I'd reccomend a mixed approach. Designate a percentage of your practice time to the exercises and theory, and learn tunes at the same time.
Oh, if you plan to sing, even a couple of lessons from a voice teacher will pay huge benifits, lest you find your tonsils on the floor during your first gig....
Good luck! And yes, those fingertips will callous.