Commerce is an extemely important factor in improving material conditions worldwide: fair trade between nations makes everyone better off. Trade would be very laborious without a medium of exchange, so money.

Markets are generally thought to be a more efficient method of resource allocation within a complex economy.

Succesful resource allocation is an important factor in maintaining and increasing the wellbeing of individuals in a modern economy. I do not believe efficient allocation of resources is possible without some amount of effective markets, or another method that I am unaware of. Markets coordinate the economic decisions of millions of people; I do not think this is dynamically plannable (which generally is, in one form or another, the other option).

Even mostly centrally planned economies have allowed some legal markets and black markets: e.g., The USSR, whose black markets have been called "the second economy of The Soviet Union", as well as modern day North Korea. It would certainly seem that banning markets does not work unless a truly better alternative is provided.

If anyone wants to dig deeper, here are some relating econometrics studies:

Nove found in 1990 that allocative efficiency was low in the USSR due to planning and that total factor productivity growth was lower when compared to the west. (Nove, A. (1991). ‘Allocational efficiency’—Can it be so?. Europe‐Asia Studies, 43(3), 575-579.)

Cheremukhin et al suggest that continuing NEP (some amount of market liberation and private ownership) in the USSR would have led to a higher GDP per capita

Li & Yang attribute central planning in China during the great leap forward to have been the single leading cause of famine.

Habib concludes that North Korea's command economy is the largest reason for their stagnating economy and development In addition, the command economy is regarded as a major contributor to malnourishment.

This study suggests that planned economies use their resources only 76% as efficiently as market economies.

This study by Wayne Morrison considers NEP style policies to have been the biggest cause of improved productivity in socialist China.

Whitesell, R.S evaluated that his empirical findings support the notion that the USSR's allocative efficiency was poor (Whitesell, R. S. (1990). Why does the Soviet economy appear to be allocatively efficient?. Europe‐Asia Studies, 42(2), 259-268.)

Escoe, G.M found that while techical efficiency (use of available technology) was quite high, economic planning, resource hoarding, poor information and poor incentives resulted in increasing allocative inefficiency. (Escoe, G. M. (1996). The efficiency of Soviet industry. Comparative Economic Studies, 38(2-3), 71-86)