Face ID for me falls short in a few ways (certainly a debatable topic, I understand):
- Face ID is less secure from a social perspective. It's a lot easier to get a false or unintended Face ID unlock than a biometric fingerprint. In fact, I've requested to Apple that we have auto-passcode options to require the passcode in certain circumstances (similar to what happens when the device reboots), like the device being moved a certain distance from the last unlock, or a certain length of time passes. All being optional, of course.
- It is less convenient. For my current iPhone SE 2020 I can pick it up and unlock it without looking at it. Although we're not supposed to do so while driving, in my state we also are prohibited from looking at a phone at a stop light or stop sign, which is annoying for me personally. Having to hold up a phone and avert my gaze long enough to unlock it is more blatant and longer in time than doing to with my hand while looking ahead.
- Touch ID is a more "positive intent" action; you must physically place the registered finger onto a specific portion of the device. Face ID just needs to see your face, which means you could unlock your phone without wanting to, or accidentally appear as if you're trying to unlock when you're not and have the device lock you out (this last one I had a coworker accidentally cause when showing off the first Face ID enabled phone, causing him to have to go through hoops to get it unlocked)
- Face ID has been shown to be less convenient in the pandemic with masks and other face coverings causing problems.
I'm sure there's more but that's the list I could think of off the top of my head. There seems, for me, to only be drawbacks or compromises and no actual benefits over Touch ID. I actually use full-finger biometric devices for my Windows 10 PCs as well, because it's easier than Windows Hello cameras, which would be the nearest equivalent scenario.
Finally I should comment that because the iPad Mini is only a game device for me, either security method is probably a bit of overkill for this device. But on an iPhone that leaves the house and can be stolen or worst-case mugged off me and unlocked with Face ID... that's a security nightmare. Arguably your primary mobile phone device is the #1 most security-sensitive device we own in 2021. There is no want for compromise, and that's why I keep the iPhone SE 2020 in my pocket. (It also looks like an ancient iPhone and deters theft by appearance alone I guess!)