Why does RBI consider coins as Asset but notes as Liability ?

Answer :

The RBI Act,1934 gives Reserve Bank of India the sole right to issue bank notes in India. Section 34 of the act further stipulates that the Issue Department of RBI will have as liability an amount equal to the total of the amount of the currency notes i.e. each note (with one exception as detailed later in the answer) which is printed becomes a liability of the RBI.
This is also illustrated by the promissory clause printed on the banknotes i.e., “I PROMISE TO PAY THE BEARER THE SUM OF…..” which is signed by the Governor of Reserve Bank of India. This liability of RBI is further guaranteed by Government of India as per Section 26 of the RBI Act, 1934.

For coins however the issuance process is different. The responsibility of minting and issuing coins remains with the Government of India under The Coinage Act, 2011.
Government has further submitted an undertaking under the RBI Act to exclusively circulate the coins into the economy via RBI. As part of the circulation process, RBI buys the minted coins from the government and hence the coins come and sit under the asset section of RBI’s balance sheet.
Coming to the exception mentioned in the paragraph above, Government of India has also retained the right to print the lowest denomination of note (i.e. one rupee note). Rupee is the unit of currency in India – the note for this is printed by Indian government and signed by Finance Secretary.
The Reserve Bank of India (RBI) considers coins to be assets as they have intrinsic value due to their metal composition. Paper money, on the other hand, is considered a liability because it is issued by the central bank and is obligated to be redeemed at face value. Paper money essentially represents a promise to pay a specified amount to the holder, and therefore represents a liability on a central bank's balance sheet.
RBI considers coins as assets because they have intrinsic value, while notes are liabilities as they represent a liability on the central bank to exchange them for goods and services.