GOG.com: Thanks to this additional security measure, your personal data and money will be even safer than before.
Ancient-Red-Dragon: That's PR spin. Your money is safe anyway, because if fraud is committed with your card, then you as the cardholder are not liable for that fraud, and you don't have to pay any of the money for debts on your card that were added via other people committing fraudulent transactions.
It stands to reason that GOG is doing this because lots of people have been defrauding them and causing them to lose money.
Your money is not safe. Online purchases use a CVV, which is plainly visible at the back of your card. Any teller can use this to make an online purchase.
"But I'm still not liable because it's not my fault!" - You are, and it is. Banks expect you to keep your information safe because they certainly can't be held liable for you posting a photo of your ATM card as so many people have done.
This is a relatively new thing (went live last year and online merchants are catching up one by one. It's provided by VISA (and I assume other card manufacturers) and everyone's happy because it's effective. You know about 2-step authentication, right? All the cool kids - Facebook, Twitter, Google, etc. are using it. This is precisely that, but for your money. You'd think that would be higher on the list of priorities.
Source: Work at a digital channels department in a bank.