[VGM911]

In the old days, warm-ups were necessary (in part) to allow the choke to adjust itself after start-up in order for the car to run smoothly/efficiently.

After the widespread adoption of fuel injection and electronic ignition allowed engine management to be better controlled, warm-ups became less necessary.

Most cars should be driven immediately after start-up, albeit gently until they reach operating temperature. Warm-ups nowadays are seen as wasteful of gasoline and therefore unnecessary/inadvisable.