Which other potential disruptive and already established technologies can you invest in as an ordinary internet user these days?
If you compare bitcoins with a fledgeling tech startup its an incredible success. The evaluation is artificially depressed through some external forces. (Possibly early adopters with a few too many coins still?)
Bitcoins do is in some sense provide a chance at buying facebook shares in 2005, or Google shares in 1999, before anyone really knew what was going to happen. But bitcoins are also a rarely potent technology. The real question is why you would be selling, desperate for fast cash or highly risk averse perhaps?