First off as an X user i can say i don’t miss Touch ID in the slightest. Face ID is way superior imo. Secondly we are talking about a few bucks more a month for payment on the X over the 8. When it comes down to it. You pay $3-4 dollars more for a superior product is a no brained.
I actually buy outright , so I don't justify items as being only x more per y period. I just compare the retail value. And one is around 1/3 more, and you pay for that "superior" difference, it's quite a price difference.