They likely went with this form factor because it allows for the camera to look forward and use that context in its responses. A watch wouldn't easily be able to do this.
I'm not defending humane but I think the main idea is that there's a camera always pointing where you're pointing that's feeding more context into the device. The projection is just one of the ways it can communicate back (with voice likely being the primary interface).
I think people also get hung up on this: at some level, we too are just predicting the next 'token' (i.e., taking in inputs, running them through our world model, producing outputs). Though we're obviously extremely multimodal and there's an emotional component that modulates our inputs/outputs.
Not arguing that the current models are anywhere near us w/r/t complexity, but I think the dismissive "it's just predicting strings" remarks I hear are missing the forest for the trees. It's clear the models are constructing rudimentary text (and now audio and visual) based models of the world.
And this is coming from someone with a deep amount of skepticism of most of the value that will be produced from this current AI hype cycle.
I believe they're saying that this type of comprehensive early detection leads to subsequent interventions on issues that would never develop into anything serious where they left alone. by increasing the number of interventions happening you could actually be making the patient worse off