In my earlier description of what I call “applied metaphysics” in the Shine Cycle, my fantasy series-in-preparation, I mentioned that “doing something metaphysically is often, perhaps usually, harder and more expensive than the ‘mundane’ way of doing it”—“cheap, easy, or effective—choose at most one.” I think I came up with this before reading Bujold’s The Sharing Knife series, but her idea of how Lakewalkers work with “ground” is very similar (although it’s borne of ethical axioms in the backstory as well as of necessity): a Lakewalker moves the ground in a glass bowl by moving the bowl by hand, but they use groundwork to “bounce” mosquitoes or to do things that can’t be done any other way, usually for military purposes (in their long war against the malices). Today I’d like to expand on this theme in my own writing with some examples of how that can work out in practice.
First, medicine: Diagnosis, except routine frequent checkups, is almost always primarily metaphysical. (There are ailments that a mage’s tests will miss, so a purely metaphysical exam is usually contraindicated, but their precision and accuracy are far superior to the best medical technology available.) Treatment usually isn’t, because in most cases the “mundane” version isn’t much less effective (if at all) and is far cheaper.
Second, “crime scene investigation”: A police force can get by without a mage for a while, but they may miss things. A private detective without a mage on call is tempting fate. The trouble is that a wizard, sorcerer, etc., can falsify physical evidence in any number of ways.
Third, flight: It is comparatively simple for a mage to learn to fly (for example, by directly manipulating the forces affecting his or her body), and most do. But for travel from place to place under gravity, this is so expensive that it’s only rarely done even by soldier-mages in combat. In low gravity (in space), on the other hand, this is actually cheaper than every personal propulsion device yet developed, and far simpler.