I've been to many really good BJJ schools.
One was more tough and rough, while another was more technical in a sport kind of way, while another one was more street and self-defense oriented, and then the last school I went to was the Carlos Machado Academy.
Carlos Machado is the head of the Machado family, which are the cousins to the Gracie family.
The Machado family has taught BJJ to many famous legendary martial artists such as Dan Inosanto, Chuck Norris, and Steven Seagal.
At the Machado Academy, Professor Carlos Machado taught me defense like I had never seen before. We focused on defense like crazy. He said that if your confident in your defense then you won't be afraid to attack, because often times when you attack your vulnerable and can get countered. Defense was the foundation he taught me.
Pretty much all the same concepts I learned from BJJ can be applied to the other styles of martial arts that I've learned. So I have been doing that. To me my training in BJJ has been the link between traditional martial arts and combat sports.
Following the defense concept I learned from Professor Carlos Machado, I feel that it's absolutely paramount to build your foundation starting with defense.
However many martial arts including Eskrima teaches offense first. I think the reason for this is that Eskrima is a military style. Which means offense-offense-OFFENSE! Defense is difficult to learn and it takes time to develop. Can't expect soldiers to always have time for that kind of study and training.
If you don't understand the value of defense then you have no choice but to be 100% committed to offense and you have to just force your way forward and keep marching and hope that things turn out well for you.
Defense is what allows you to survive under the worst conditions. From a self-defense point of view that is where it's at.