One reason for that is that the financial system will remain under stress in many countries for some considerable time. For example, banks that hold large quantities of domestic sovereign debt could be exposed to renewed funding stress if there was a further deterioration in the euro area sovereign crisis.
To ensure that banks can fund themselves if strains in interbank markets return, it is desirable to retain some of these tools. In addition to retaining greater flexibility in liquidity management, IMF (2010) argues in favour of requiring banks to hold greater liquid reserves to help them absorb better liquidity shocks.