It is clear that is what you assume. My interpretation is that Boeing leaves it open. My company encourages autobrake usage. Over the last few years we have gone from your approach or something similar to the view that the autobrake is a useful tool in normal operations. Ten years ago for example the view was that autobrake one was for the limp wristed. Now we encourage its use where appropriate.
If you were involved in a runway excursion do you think the investigator would ask if you had selected autobrake? Some things are black and white, stabilised approach criteria for example. But autobrake usage is left open and I suggest people follow their own company guidelines.