I am not a geek, nor some uber nerd. Tarsnap seems to be designed exactly for them. I once asked about a GUI of Tarsnap in one of the threads on HN few months ago and the very mention was heavily downvoted. So, I just think I don't fit in the fan-circle and honestly I am fine w/o it.

Another reason is price. I will put a good amount of data there lying unused for a long period so the extra dollars shall count a lot and since I'm searching for a client that would have de-duplication that one benefit would be settled too (as I've heard Tarsnap has de-dup).