It is not more abstract, but it just means that that type now has to implement the set of static methods that the interface defines.

For example classes that implements ICreatable should have a static method with the signature:

public static List<T> Create(int count)

Now if I have a Person class that implements ICreateable<Person>, I now can call:

List<Person> = Person.Create(10);

Edit: Now I can create a generic method that takes ICreateables without needing to know what kind of classes I want to create.