Eh? The Time Cube guy IS very obviously a kook. (Aside: If you need a good laugh, this radio show interviewed him - TWICE - pretending to play along with him. He's absolutely nuts.)

Attempting to brand someone as a kook only works if there's something kooky going on. Bitcoin is exactly what it claims to be. One might find a security hole in it, but that's about all you can credibly do to discredit it.