Computation Does Not Live Outside the Physical World

Software can feel immaterial, but instructions require hardware, and hardware behavior is connected to energy and heat. Calling something virtual does not remove its physical limits.

A query may be cheap on a small dataset and expensive on a large one. The user's click can look identical while the internal work changes dramatically. A small interface action is not necessarily a small physical workload.

When discussing optimization, it helps to name what is actually reduced: bytes transferred, copies, computation, or waiting time. Those are not the same change, and improving one can increase cost somewhere else.

I do not think of software as a world without matter. Its flexibility is enormous, but it still runs on physical systems and through time. Remembering that relationship keeps efficiency from becoming only a question of elegant code.

Source: official reference.