It’s the other side of the transaction that people should worry about more. If you make a payment to the VPN company through Credit/Debit card or PayPal, either PayPal or your bank will have a record that you use that particular VPN. If the bank or PayPal are ordered to hand over information about you by n authority (such as the police), they will consequently also know you use that VPN. Although I suppose that information may be worked out if your ISP keeps detailed enough data about your internet usage, and enough time is taken to sift through it to find that you are making a connection to the VPN’s servers. Still much more private than leaving a trail through your bank etc.
TL;DR to prevent the bad guys from knowing you use the VPN.
It’s the other side of the transaction that people should worry about more. If you make a payment to the VPN company through Credit/Debit card or PayPal, either PayPal or your bank will have a record that you use that particular VPN. If the bank or PayPal are ordered to hand over information about you by n authority (such as the police), they will consequently also know you use that VPN. Although I suppose that information may be worked out if your ISP keeps detailed enough data about your internet usage, and enough time is taken to sift through it to find that you are making a connection to the VPN’s servers. Still much more private than leaving a trail through your bank etc.
TL;DR to prevent the bad guys from knowing you use the VPN.