That seems, I don't know, silly? It feels mean to say silly, but I can't think of a better word. Why not use 6 digits, or 7 digits, or 20 digits? Then you'll really trigger some long-term thinking in your readers. I could start writing all my dates in years since the birth of the universe, to give people a feel for the long past and how insignificant their little lives are. But this defeats the purpose of dates, which is to communicate facts about time using a common system of numbering.