The part where it talks about gi training is complete BS. The gi makes training LESS realistic (I train in the gi 3 times a week and always have) the chokes, sweeps, and hold downs which are utilized with the gi on are often impossible to pull off on someone wearing everyday clothes.
You are not going to put me in spider guard when I have a t-shirt on.
I find it odd that Jiu-Jitsu chooses not to rely on strength because it might not always be there, but they find it perfectly acceptable to rely on clothing that most likely will not be there. Also in Brazil no one is wearing anything resembling a gi.