To my mind, BJJ, wrestling, Judo, Sambo, and related arts are just different facets of the same gem. They all come down to understanding base, posture, structure, force vectors, and leverage and using them to manipulate an opponent's body while keeping the opponent from doing the same in return. The variance in training mindset and application come down to differences in culture and/or competition rules. The underlying principles are (IMO) more important than the differences. (Although it's worth exploring the differences, since they illustrate how a principle may apply in difference contexts.)