The trouble is that by human intuitions, you think there's a strong inverse correlation between being hard to guess and easy to remember; but that's not always the case.
It's hard for humans to remember meaningless conjunctions of symbols, so we think they are hard to guess; so we err on the side of making them too short. Contrariwise, we think a sequence of just four words couldn't possibly be hard to guess because it's so easy to remember, but it's only easy to remember because we can use the meanings of the words to form an idea or image, something our brains are built for (unlike strings of meaningless characters).
This is why the word technique is better: it corresponds better with how we remember, while reducing two other risks: the risk of losing your password - non-trivial - and choosing too short a password.
It's hard for humans to remember meaningless conjunctions of symbols, so we think they are hard to guess; so we err on the side of making them too short. Contrariwise, we think a sequence of just four words couldn't possibly be hard to guess because it's so easy to remember, but it's only easy to remember because we can use the meanings of the words to form an idea or image, something our brains are built for (unlike strings of meaningless characters).
This is why the word technique is better: it corresponds better with how we remember, while reducing two other risks: the risk of losing your password - non-trivial - and choosing too short a password.