This is somewhat analagous to trying to Direct Learn tennis. Yes, I can PR 100 books on tennis but until I go out and actually feel the racket hitting the ball, see the effect of forehand, backhand and spin, etc. I don't _really_ know anything about tennis.
NLP is experiental, as are most skills. Direct Learning can give you a good running start but until you actually experience it firsthand, it is a very pale, shallow kind of knowledge.
I have a stack of about 30 NLP books that I Direct Learned while getting my Practitioner Certification. In the intervening time at other seminars people were amazed at how well I understood the material. Now, two years later at the end of my Master Practitioner certification, everyone in the class wants to practice with me bacuse I understand the material very quickly and can apply it very precisely.
Do I think Direct Learning helped me? Yes - immensely. Would Direct Learning alone have been as effective? Abosolutely not.
Good luck learning NLP. Deciding to take the Practitioner course was one of the best decisions I've ever made.