The output length gives you the size of the AES key used: 128, 192 or 256 bits. If you are simply looking for plaintext AES keys in your binary, will not find them they must have been expanded by the key expansion algorithm.

might give some hints if high entropy sections are found trying to cover up a hardcoded secret.

The blocksize is increased to 4096 bytes from the default 100 bytes so that the entropy search /s can work on reasonably sized chunks for entropy analysis. The sections flags can be applied with the dot operator, and then looped through px 32 @@ entropy*.