I've made the same comparison to judo on here before too. In judo the grip battle is the key part, its decides the whole fight. Whoever wins that throws the other guy because they know exactly what they want the particular grips for, have drilled it to death and immediately use them.
Marcelo's effectively doing the same, he's hand-fighting to dominant grips and attacking off them immediately. If he gets them he gets to do what he wants and you get no chance to do what you wanted to do. Its more specific than just get a grip even if its not perfect; each of overhooks, underhooks, Collar Ties or 2-on-1 grips are all very strong controls. Winning the hand fight lets him dictate what happens next and the other guy is forced to be reactive. He doesn't have a way to force his game on Marcelo like how getting out-gripped in judo means you've little or no chance of throwing the other guy.
I think it's more akin to grip fighting in wrestling, and naturally so because Marcelo mixes wrestling in. Without a gi you cannot maintain a grip unless the grip is by nature dominant. In Judo I can still throw with an "inferior" grip because of the leverage and distance involved, whereas in wrestling you really have shit if you lost the grip battle and are wide open.
This principle extends to a seated guard in no gi. You are always in danger of being run around or pressured, so if you play head on you have to win the grips.
I like how he has linked everything so far. Some awesome details (IMO) on hitting the Marcelotine from Butterfly on the 2nd volume (as well as that inverted arm bar he does - when and why you go for it).