The “dynamic” aspect of this feature is the ease of switching from one outbound number to another by entering a code combination on the phone. Each user already has their own unique, custom caller ID that can be switched to any number on the account, and switch back just as easily.
Represent multiple businesses on the same phone system, and present the number from your account that is most appropriate for the call.
Give the appearance of a local business in other markets, and let your business appear more personal and professional to those you call.
People are less likely to screen your call.