It's undeniable that saving files under traditional folders grants the most convenience and flexibility, however, saving files this way may also have limitations. For the following considerations, Eagle uses the "Library" structure to save software data.

Reduce hard disk reading and writing frequencies.
When you move images to different folders, Eagle only needs to change the category properties of the images and there is no need to change the actual directory of the images in the hard disk.
Allow images to be saved under multiple categories
Since the images are not actually saved under a specified folder, Eagle can easily save the same images in multiple categories.
Reduce unnecessary hard disk file scanning and monitoring
Because the library is only readable/writeable exclusively to Eagle, there is no need to monitor whether the contents in the library are modified by other programs from time to time. By doing so, Eagle avoided unnecessary hard disk scans (Which is the main reason why software like Adobe Bridge is criticized).
Reduce the effort to find files
We hope to offer different Eagle experiences compared to the original file managers. Whenever you want to view images or assets, instead of finding files through layers of directories, the only thing you have to do is open Eagle. (Like the Note application, when you need to find a note, you only need to open the Note application and don't need to recall the saved path or search layer by layer.)

Overall, Eagle's storage structure prioritizes "performance" and "functional scalability", at the expense of having Eagle library flexibly accessed by other software. If you want to share the images saved in Eagle with other friends in the traditional folder way, you can do it with the "Folder Export" function.

Why does Eagle use a library instead of an actual folder to store data?