If any joint account holder tells the bank, or the bank find out that the joint account holders are in dispute, they may ‘block’ access to the account.

This means that no-one will be able to withdraw funds from the account.  That means that no expenses can be paid from that account – not even joint household costs.

Deposits to the account may continue. 

The bank will continue to pay interest on the credit balance in the account.  The bank will only ‘unblock’ access to the account when they receive authorisation from all account holders.

Turmoil results.  And in a protracted divorce or dispute funds would be locked up for a very long period.