The concept of a file only sort of gets modeled within the scope of what a directory is, with generic tooling; otherwise, you just have "documents". And there is also a big difference between really knowing what it is, and doing it a handful of times.

Like, imagine using an iPad your entire childhood, and then maybe getting a Chromebook. You just aren't going to have the same level of comfort with what files are or how they might work, as you don't really ever think in their terms.

Do you need to actually "download a file" to apply to a University, or is it a captive web form now? If you do, imagine doing it on an iPad: you download the file and it goes into some transient Downloads UI before getting opened directly by your word processor. Certainly creating a resume doesn't cause much interaction with "files".

You certainly don't, anymore, use files to move pictures from your phone to your computer: you use a cloud service like iCloud Photos or Google Photos, which automatically "syncs" all of your data from your phone to the same app on your desktop.

If you want to create a meme on reddit--which you certainly are doing on your phone or iPad, as a computer is complicated and lame--you aren't using generic tools to edit files you saved to disk: the closets thing to a filesystem you are working with is your camera roll, working in an app that let's you add remix from it and then saves the result back to it.

People at companies like Apple have gone to such great lengths to hide the complexity--and limit the ways of composition--of software that, at best, "Files" is just a sort of confusing app you might sometimes get forced to use only if you have no other reasonable option, and so you don't have a mental model for it; and even then, it's separate from where your data "really is".