Let's not confuse the obligation to submit notification with the methodologies for submission.
You must submit details if you're intending to operate in controlled airspace other than Class E. (How else are you going to obtain the requried clearance ....)
There are various ways to submit those details. Submitting by radio is the least preferred method. As FTDK notes, that can lead to delays.
Others have pointed the way to the AIP water. It's up to the horse to decide if it wants to drink...