I think you don't need to be a rocket scientist to use coinbase.com, for example.

I'd say it's just as transparently stupid to give your Bitcoins to someone else. And yet tons of people use web wallets, which are often hacked (or "hacked").

Dealing with the pain of getting bitcoins doesn't make you smart, and it certainly doesn't make you invulnerable to greed.

How does anyone with the ability to navigate the fairly pain-in-the-ass process of getting [any large amount of any currency] fall for something so transparently stupid?

And yet they do, all the time.

Greed.

Why do people send their banking credentials to some random guy in Nigeria?

Same reason.