I learned an interesting thing recently. A teacher I work with connected an iPad to a chromebook's USB port. I was pretty sure that it wouldn't do much other than charge the iPad off the chromebook's battery, but I was wrong.
Trying to show the teacher that she couldn't synchronize data between the iPad and chromebook that way, I opened the Files program on the chromebook. In Files, in the same sidebar area that Google Drive and other things appear, there were two listings for the iPad. When I clicked on one, nothing showed up. When I clicked on the other, a DCIM folder showed up. Most digital cameras store their data inside a folder named DCIM and it appears that iOS follows this standard. So ChromeOS basically said, "OK, here are the photos on that camera you just connected," and offered up the files. We were able to drag-and-drop them into Google Drive, allowing her to copy them over.
Of course, she could have done this with the Google Drive app for iOS. This USB method does have a few advantages, though.
For one, it allows a teacher on a chromebook to collect photos off of their students' iPads. No accounts are required. You don't even need software from Apple's App Store. This could be useful in schools that provide iOS devices (e.g. iPads or iPod Touches) to younger students. It could also be helpful for people who have iPads but don't use Google Apps for Education. In that situation, the students wouldn't necessarily have Google Drive accounts to upload their photos into. There are also situations when students don't have Apple accounts and, therefore, can't download apps like Google Drive from the App Store.
I suspect there are other potential uses for this that I'm not thinking about right now. If you have any, please tell me about them in the comments section below so that other readers can benefit, too.