The advantage of this would be sending a message which cannot be known until a point in the future - sort of like a time capsule with a lock that only opens on

The advantage of this would be sending a message which cannot be known until a point in the future - sort of like a time capsule with a lock that only opens on a certain day, but way more secure. While, for most purposes, merely storing encrypted information and only revealing the key later might be better, there are probably some things very paranoid people could use this for (a message that arrives after 100 years, for instance, could reveal all sorts of things, as the author would know that he would be dead by then). However, it's not very useful for practical purposes.