No, it wouldn’t be. The idea is at least over half a century old (https://en.wikipedia.org/wiki/Tricorder)
Executing upon that idea and actually building it would be revolutionary even if that meant building a single one at the cost of a trillion dollars.
Unfortunately, I don’t think we can even put all the necessary sensors in a device that size, let alone power them there and turn their measurements into a diagnosis or, better, treatment plan.
An iPhone cannot remotely reliably count how many steps I set in a day, heart rate measurement in an iWatch doesn’t work well during exercise, non-invasive blood glucose monitoring is a research project, etc.
Because of that, I think that replacing primary care doctors by some magical device will mean heavily increasing the load on secondary care workers because the number of false positives would go up tremendously. Net effect would be higher healthcare costs.