You definitely can, geophile is just being obtuse.

>For some apps, you can make the function keys display permanently in Touch Bar: In System Preferences, choose Keyboard. Click Shortcuts. From the left sidebar, select Function Keys. Click the “+” symbol, then navigate to the app and select it.

From: https://support.apple.com/en-us/HT207240

If you want always function keys, you can do that too:

>If you prefer the top row of keys to always behave as standard function keys without holding the Fn key: Choose System Preferences from the Apple menu. Click Keyboard. Click the Keyboard tab if it's not already highlighted. Select "Use all F1, F2, etc. keys as standard function keys"

From: https://support.apple.com/en-us/HT204436

I actually looked through System Preferences. I did not see a new Touch Bar option, and it didn't occur to me that a non-keyboard device would be configured under Keyboard. My bad. While this does improve things, I would still rather have real keys. Tactile feedback is a thing.

Note: the second link only applies to non-Touch Bar devices.