I guess, it should be-

There are a variety of reasons why you might want to use a MAC based on a symmetric cipher, rather than using one based on a cryptographic hash.

to

There are a variety of reasons why you might want to use a MAC based on a symmetric cipher, rather than using one based on a message digest.

any idea or thoughts?

Ah, okay, wasn't sure if this was a question.

Actually, in this case, both sentences say the same things. You'll find if you start looking at the IETF standards for example that people use the terms "cryptographic hash" and "message digest" interchangeably. One of the reasons for this is that message digests can, and are, often used as hash functions in a variety of ways, from basic table storage to algorithms like Bloom filters. The distinction between a regular hash and a cryptographic is the nature of the algorithm used - random bit changes in the input of a cryptographic hash should always call an unpredictable change in the resulting cryptographic hash.

Regards,

David