My understanding is that it's to comply with money-laundering laws. They limit the size of the transaction per-day and per-person.

I haven't bought bitcoins (online or through an ATM), but it seems any purchase of bitcoins from any electronic money transfer would have the same issue of breaking anonymity. I suppose there are ways to anonymize the funds once you have them.

This is it really. There's a limit to the amount of cash they can do per person per day, and this is a way to ensure people don't go over the limit.

It doesn't seem like the scanner is required for these machines and it does so using palm-vein scanning, not fingerprints. They are doing so to prevent any single user from withdrawing over a legal limit in a day.

"If enabled, the Palm Vein Scanner can limit a user's daily transaction amount by taking a unique, anonymous (no fingerprints) infrared picture of a customer's blood vessels to assist in AML compliance."

It's difficult to argue that information which is specifically used to uniquely identify you is "anonymous".

What anonymity of Bitcoin? Nothing in the design of Bitcoin protects anonymity, nor is it a clearly stated security goal.

I think they are trying to avoid fraud. Since they seem to be limiting to amount you can withdraw, they probably need some way to authenticate you.

Not to mention that that is associated with a government ID and a photo. Why not just use a bank account...?