In reply to Kapu Gopal:
I guess your phrasing led me to believe you were specifically referring to “bit” only. As the LRM states under packed arrays -
Packed arrays can be made of only the single bit data types (bit, logic, reg), enumerated types, and recursively other packed arrays and packed structures.
What is a byte? It really is bit [7:0] but signed. See the redundancy? Additionally, arrays can also be 4-state like logic and reg. These are particularly useful in modeling memories.
Unpacked arrays however can be of any datatype. So, this feature of mixed type arrays being limited to “single bit type (bit, logic, reg)” comes from the packed dimension.