I saw an ad for a vpn provider recently where they claimed that, without using a vpn, my credit card information is "wide open to hackers" while shopping on-line. I guess the implication here was that vpns are encrypted, while regular connections are not. However, isn't https encrypted, and therefore safe to use without vpn? And aren't on-line stores required to use https or other forms of secure payment?
If you enter your credit card information on a site which is not protected by HTTPS then a VPN will provide at least part of the missing protection, like addressing the problem of an attacker in the local WiFi hotspot.
If you enter your credit card information on a site which does not properly handle this information neither a VPN nor HTTPS will not protect you. This might be cases where the site accidentally puts this information online by itself or where it got attacked and the data exfiltrated.
Similar if you enter your credit card information on a site which is already compromised the attacker might grab the information right where you enter these. A VPN will not protect you against this and neither does HTTPS.