A better question is if people are going high-res, why not go high-res with tests whose accuracy is known, and for which there are useful, data-driven treatments?

Instead of casting a net of unknown quality every month, comparing against a null dataset (there does not exist a large dataset of these scans with outcomes for given markers).

Why not advocate cheap, easy blood/urine tests with higher frequency? Those tests do have large reference datasets with outcomes. And they have prescriptive value: there is likely more benefit to catching hypertension or diabetes earlier in more people.

True, though those things don't have to be mutually exclusive.