Digital currency/bitcoin will never replace money and people will still use the paper money because The paper currency will never be replaced.
Paper money is ruling the world since its inception and no other currency can replace it in future, people are more comfortable in using fiat rather going for digital stuff.
Yeah from its existence paper money is ruling the world. This could continue till the end of the world and the future will continue to use digital currencies as an alternative but would never replace the use of paper money.