They both have their uses. Yes with Touch ID you can have the phone unlocked before you even take the phone out of your pocket, so faster in that sense, but we’re talking a second because Face ID can activate as you lift the phone to your face. I’m looking forward to when you can use both and the Touch ID under the screen is rumored for next year. Some people have issues with Touch ID for a variety of reason, like dry/cracked skin, dirty hands while cooking, chalk on hands while at the gym, wearing gloves etc.