There are several scenarios where one day insurance may be needed. One of the most popular is making sure you are insured when borrowing a friends car. Securing an additional policy for this could protect a no claims bonus built up. This could therefore be an economical option for careful drivers.
Temporary insurance also allows cover to be provided for additional drivers sharing the driving on holidays and other longer journeys.
Insuring an overseas visitor while they are here to drive is another popular reason. As is requiring short term car insurance when buying a new car and needing to take it home. Taking a test drive and requiring insurance for a day can be another scenario.