Why is planned economy not as good as market economy?

The term "market economy" was actually invented for "planned economy," just like the concept of "Western medicine" was invented for "Traditional Chinese Medicine."
Before the concept of "Traditional Chinese Medicine" was created, no one ever thought that medicine needed to be divided by country or ethnicity.
Medicine is medicine; there is only validated medicine and unvalidated medicine.
Similarly, before the concept of "planned economy" was invented, humanity had never realized that trade activities also had a name called "market economy."
Economy is economy; there are only spontaneously formed economic orders and deliberately formed economic orders.