That is a great device indeed and can definitely help in the identification of Covid-19 affected individuals. However, there are many people who don't show any symptoms even if they have Covid-19 and this is where this device will be ineffective. Besides, it can detect high temperatures so a normal person with fever might be mistakenly treated as a Covid-19 patient if this device is used to detect symptoms.

But this device is still useful and will serve humanity even after this pandemic is over.