Question

why is money accepted as medium of exchange

Answer 1

Money is accepted as a medium of exchange because it is authorized by the govt. of Indian and the RBI , this authorization gives money its value otherwise it nothing other than a piece of paper.

Answer 2

money is accepted as common medium of exchange because the value of money never changes. It remains contant forever.
benefits of money are

no need of double coincidence of wants

fixed value

easy to carry

easy to maintain