unzip returns exit code 1 on empty archive

I have an valid, yet empty zip archive:

$ file 22.zip 
22.zip: Zip archive data (empty)

$ xxd 22.zip 
00000000: 504b 0506 0000 0000 0000 0000 0000 0000  PK..............
00000010: 0000 0000 0000

Trying to list the archive content or unzipping the file gives both a warning and returns exit code 1.

$ unzip -l 22.zip; echo $?
Archive:  22.zip
warning [22.zip]:  zipfile is empty
1

$ unzip 22.zip; echo $?
Archive:  22.zip
warning [22.zip]:  zipfile is empty
1

I understand the warning, but the exit code seems wrong. There is nothing wrong with an empty file; for example running cat on an empty file yields exit code 0. What is the reasoning behind unzip returning an exit code 1 on a valid, yet empty file?