What happens when you use diff to compare two binary files that are not identical?

(You can use gzip to create the binary files.) Explain why the diff
output for binary files is different from the diff output for ASCII files.

When you use it to compare binary files, diff displays a message saying the
files differ when the files differ or no message when the files are the same.
The diff utility compares ASCII files on a line-by-line basis; it is not designed
to compare binary files on a byte-by-byte basis. Use cmp to compare binary
files in that manner.