[m463]

That is the exact opposite of this problem.

Download over usb allows you to download the kindle ebook purchased on amazon to your computer. That gives you an offline copy of your ebook. You can then download it to your kindle over usb.

But since you have the file, you can ALSO send this file to another ebook reader. I believe some ebook readers like pocketbook can read .azw files directly. Readers like kobo might need conversion to epub or kepub.