I deny it. Face ID on my XR is way faster than Touch ID on my wife’s 8, or my iPad Pro 10.5, or on my old 6S or SE (which admittedly had the first gen sensor) - I’m not talking about the actual reading of the print/face itself necessarily but the whole process.
With Touch ID there’s always that moment needed to locate and touch the home button; sure you can get very slick at that and be touching it before you’re looking at the phone, but as soon as you’re looking at it Face ID unlocks anyway, you’re just saved the fumble first. I get far, far less misreads or failures with Face ID too.
Where Face ID really comes into its own is in-app authentication. With banking apps, PayPal, code generators, secure office apps (like my work office 365 suite), even just logging into websites using safari keychain - these all require authentication which with your 8 or any Touch ID device means stopping everything and reaching for that home button again. Face ID on the other hand just happens right in front of you, no effort required.
As for your other comments re speed of use, you’re just talking about your own muscle memory and how it’s tripping you up on X phones. I went from the SE as my daily phone to the XR and am totally comfortable with it, and fast.