>>11925464
.a2r is overkill for everyday use. It exists to preserve entire magnetic structure of a floppy disk, producing an image several times larger than any data actually stored on a disk. Important if you want to create 1:1 replicas of original disks, but you don't need all that information to play games. .woz format was created as a compromise to contain enough data to replicate disk idiosyncrasies without bloating file size.
If you download any 4am release from the Archive, he usually includes an extras .zip which does contain .a2r files used to dump or crack a disk.