My philosophy with regard to music has always been this: it's not the destination, but the journey. If you spend all your time doing scales and drills and such, but hate doing them, at the end of the day you're going to associate music with those bad feelings, and move on to something else. If you enjoy learning music from tab, go for it! The love of music and playing music is the most important thing.
That said, there are many important things you will learn from these lessons or a private teacher that you will not learn from tab. I spent about 6 months playing on a Seagull acoustic using chord diagrams and tabs until I found this site. I'm about halfway through Guitar Fundamentals 1, and I've learned more about technique (right and left hand, stuff like muting and parts of the guitar) in those 15-20 minutes of video than I did in 6 months of tab. Has it helped my playing? Absolutely! Are there nights where I don't even touch the website and just plunk around? Absolutely!
It all comes down to how you want to play and how you want to learn. There are concrete and important things you can learn by studying the lessons and improving your technique, but don't let it overwhelm the main reason you're playing - the enjoyment of music.
John