Oh! Skepticism is good. And this type of tech is very good for goal-directed management of fluid resuscitation! Severe peripheral vasoconstriction, not so much, as you mentioned. Really, in my first-hand experience most clinicians use the tech to follow trends in the ICU or surgery.

I wouldn't call the claims Theranos-level, but at the same time I don't see how this is any more useful for the general population than the standard automated blood pressure cuffs. Maybe that will change as things evolve!

This article has a nice review of the history-- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4312947/.