I speculate it's for consistency with VLAs that are not function arguments, which is the more common use for VLAs. The original purpose of VLAs is to let you s

I speculate it's for consistency with VLAs that are not function arguments, which is the more common use for VLAs. The original purpose of VLAs is to let you stack-allocate an array with a length that is not known at compile time. In ANSI C you must heap-allocate such arrays, using malloc.