Instructional materials are a training aid, not training. That goes for BJJ or anything else.
If you're an experienced martial artist who has mastered the fundamentals, understands the nuances and subtleties of technique, and can critically analyze what you're seeing in some DVD that is geared to your level of skill, they can be good ways to analyze techniques from a point of view other than the one you have during class (that being the point of view of a guy with his face mashed in to the mat. You may also pick up helpful drills or approaches to training that might help you tweak your game a little.
But to start from Square 1 with tapes, videos, booklets, an so on? There are few worse mistakes you can make, quite frankly. Whatever it is you're trying to do-- get out of some dudes' guard, hit your tee shots straight, trap a soccer ball while it's in play, sink baskets from the free-throw line-- at some point you will need to spend time doing it under the watchful eye and experienced tutelage of a coach or trainer. Otherwise, the most you can hope to accomplish is develop a repertoire/ arsenal of crude, middling technique riddled with mistakes you couldn't correct because you didn't know they existed in the first place, and which you will also now know how to apply where they are appropriate and do the most good.
It only gets worse if your prayers are answered and a proper Judo/Jujitsu school comes to your town and opens its doors to people eager to train. If you've been doing the "self-taught" thing long enough prior to this, you can probably count on spending many irritating, frustrating, and maddening weeks or even months unlearning bad techniques and purging them from your trainig.