To be 100% honest it’s probably a few bucks more expensive because of the amounts the gift cards come in doesn’t exactly line up with their monthly plan. The reason I do that is to keep my credit card info out of their hands and to prevent there being a month on my credit card that I didn’t want due to me forgetting to cancel in time. The part about the credit card info being in their hands is because I watch a lot of security and privacy blogs and I hear more and more about data breaches (note I am not singling Netflix out for poor security) and tracking, but also data on users being sold as a secondary revenue source. When I sign up with a gift card I user a service like simple login to create an email alias (check out their free tier) which redirects to my normal email. So no user data to sell. Typing this out I realize this is not an option (affordable or convenience) for everyone so using your regular credit card and cancelling in between series would next best option.