Credit cards are bad for privacy
Credit card companies track your every purchase, and this data to advertisers.
Visa, MasterCard, American Express and Discover are all guilty of selling consumer purchase data to data mining companies, and allows advertisers insider information on your demographics, habits, and guilty pleasures. The sad truth is, if you are using a card instead of hard cash, your spending habits will be out in the world for companies to take advantage of.
How do I protect my spending privacy?
Credit cards are certainly convenient, so when you choose one, be careful to select those with explicit privacy policies that prevent the selling of consumer data. Apple Card has an explicit zero-knowledge policy regarding consumer purchases: Apple doesn't know what you've purchased, and Goldman Sachs, the bank supporting this credit card, will not sell data to third parties.
Stay away from Google Pay: Google uses it's consumer purchase data to run services like AdSense and recommend you Youtube videos.