If I were to boil it all down, it would come down to this: You use your imagination, and invest yourself into the game. Although as he suggests, a lot of that depends upon how well the game allows you to do that. I might suggest, alternatively, is you get out of it what you put into it, with a multiplier provided by the game. A good game has a high multiplier value. A crappy game approaches zero.
I read Scott McCloud’s acclaimed book, Understanding Comics, a few years ago and it really opened my eyes to things. The most powerful concept I learned was how more abstract art can be more compelling, as it allows the reader / viewer to project themselves onto the page. A detailed, more realistic character comes with baggage. A more abstract, cartoony character is more of a blank slate, compelling the reader to fill in the details – usually on a subconscious level.
I think that applies equally to games. Thus the continued success of the “silent hero” archetype in RPGs.