Passage: In 1935, the Central Government enacted currency reforms to limit currency issuance to four major government controlled banks: the Bank of China, Central Bank of China, Bank of Communications and later the Farmers Bank of China. The circulation of silver dollar coins was prohibited, and private ownership of silver was banned. A new currency issued in its place was known as fabi (Chinese: 法幣; pinyin: fǎbì; Wade–Giles: fa-pi), literally "legal tender".

Question: Why was fabi used?
limit currency issuance