The palm vein scan is used for obeying the limits in the ATM. And this is exactly what many people complain about. And I would be skeptical myself as well to provide this. No bank requires any of this, why should I provide it to someone whom I don't really know well.
I think you have a point there. I think Robocoin is trying to appease US regulators by providing high tech identity verification. Unfortunately ordinary people don't care so much about that, and that's who would use their machines. Here is a currently high voted post on Reddit:
Tried the first Bitcoin ATM in the US tonight, my experience
So, I decide I'm going to buy US$20 worth of Bitcoin. I get my $20 bill ready and go to the machine, and tell it I want to buy Bitcoins. How hard can this be? I can buy $20 worth of alcohol at the very same bar in about 20 seconds.
So first it asks me for my cellphone number. Not feeling the anonymity. Sends me an SMS and asks for a verification code.
Then it asks me for my handprint. Immediately I'm feeling like I'm going through US Immigration in an Airport. Still not feeling the anonymity.
Then it asks me for my driver's license. Ok, so now I'm definitely not feeling the anonymity.
Then it tells me that I need to go away and come back in 5 minutes while they approve my account. At this point, and I'm fairly enthusiastic to make this work, I'm thinking "fuck this shit". Meanwhile I've given a company I know very little about my cellphone number, every piece of information on my driver's license, and my handprint.
Then I get a text saying that they can't approve me automatically and it will take longer than 5 minutes. Definitely fuck this shit.
What the hell is the point in having an anonymous decentralized currency if you have to get an anal probe just to exchange some $$$?
I really wonder whether Robocoin are actually forced to do this by law or if they just think that they'll be left alone by the government if they make the process awful enough.
If it's the latter, they might succeed in being left alone, but unless their target market is the unlikely intersection between hardcore bitcoin enthusiasts and those that enjoy privacy-killing tedious anal probes, they are in big trouble as a company.