The numbers-on-the-front design was necessitated by offline credit card processing, in which the card was put on to a device that imprinted the card on to a piece of carbon paper for later processing. This is the reason why the numbers were embossed/raised from the rest of the card. See the below image for an example.
-- Image source: Wikipedia --
Since "nobody" uses this method of card capture for transactions any more, there's no need to have the embossed numbers on the front of the card. This definitely simplifies the design of the card. Aside from that, keep in mind that online transactions typically have a number of layers of security implemented by vendors and banks that may include confirming the Postal Code of the billing address, two-factor authentication for unusual transactions, manual flag and review by fraud detection agents, etc. Just because someone gets a snap of the back of your card doesn't mean they can necessarily use it for long.
In person purchases require either NFC or chip transactions. The more prominent concern regarding the newer cards are not gaining the numbers on the card, but using a NFC reader to capture the NFC data, which can then be used with a relatively inexpensive device, such as cards designed to mimic multiple physical cards at once. That said, I believe the newest batch of cards use a challenge-response system, so NFC capture isn't as big of a deal as it used to be.
Overall, the position of the numbers on the card doesn't matter. There are plenty more security features that most people don't even realize are in play when they use these chip cards. And, of course, virtually every Visa and Mastercard you'll be offered have a zero-liability fraud guarantee. If someone somehow successfully "steals" your card, you can get that money back (though, in practice, it usually takes 1-2 months, so it's a major pain for the paycheck-to-paycheck people out there).
