In other words, if President Thomas Jefferson had invented a light-speed capable spaceship and launched it at the same time Lewis and Clark embarked on their voyage of discovery, the space ship would now be a little over 2/3 of the way to their destination.
Exactly. The science is interesting and tickles the natural human curiosity. But it is irrelevant for us today. I suppose it's good practice for our descendants that might be able to do something with it, in say another 1000 years.