Serious complications can be quite subtle that unless you answer questions, they may be missed. Having someone come in, listen to your heart and lungs, ask a few questions can't really be replaced with machines.
(It wouldn't even need to know what the odd thing represents; just that it's out-of-expectation enough to require someone to come over and check on you! A bit like asking a family's child to watch grandma while you speak to the mom and dad. All you want the child to do, is to freak out and get your attention if grandma does anything other than what she was already doing!)
Doctors not having to manually probe any signs of heart/lung problems each time they're in the room, would mean that they get either get more time to test each patient for consciousness/lucidity; get time to check on more patients; or (my preferred option) are able to make each check-session shorter and less invasive (no need to sit the patient up to listen to their lungs through their back, for example), and thus less disturbing of a patient's sleep quality (because it's easier to go back to sleep after a short conversation, when you haven't had your blood pressure spike from sitting up.)
The thing people don't seem to understand is the fact doctors also monitor consciousness. Depressed mental state is also a sign of blood loss. The patient's neurolopsychogical state is important information, it has diagnostic and prognostic value.
The most basic way of evaluating a patient's neuropsychological state is to bother them with questions.