Monarchy vs Democracy
To reign a country the reigning should be continuously. In monarchy regimes, father kings not giving the heirs to the sons but they should asking the sons to complete the unaccomplished plans and keep secret things of and for the nations.
In nowaday we follow democracy governments with legislature, executive,and justice in which the presidents, the representatives, the senators are changed at a certain period of time, therefore in order to have a continuation of reigning a country the handing over ceremony is so important.
Secret documents should be kept in national storeroom and the active authorities have to read them in protecting rooms secretly. No leaking allowed.
Trump the 45th president of the USA didn't hand over properly and he took secret documents to his own house. He looked down upon the Americans.