I believe this is for the fringe cases where you have been diagnosed with hypertension, but your apple Watch does not tell you that you have hypertension risk, then you may decide to not take your drugs, since your watch told you all clear. This could trigger lawsuits if complications set in when you decide not to take your drugs because of "lack of alarm"

Then you get a new fringe case: you are not yet diagnosed with hypertension, but you are aware that your apple watch has that functionality so you decide you don't need to be diagnosed.