Those instructions are good enough to keep you from getting in any kind of trouble when you gamble but this is not enough to become a profitable gambler, as not a single one of the points given deals with how to overcome the house edge the casinos have over the player, and without it then no strategy can become successful long term.
Now it is true that doing such thing is possible on only a handful of games, which means the number of games gamblers can pick are extremely limited if they want to become a profitable gambler.