Answer:
it promotes specialization by overcoming the problems with barter.
Explanation:
When economies are specialised workers focus on producing what they have competitive advantage in, and all other goods are purchased with the use of money. This increases economic efficiency and improves quality of products.
On the other hand the barter system involves exchange of goods between people. To get what I want I must provide the other person what they want. This promotes diversity of production with one person producing wide range of goods he does not have competitive advantage in.
So money increases economic efficiency.