This eliminates any formatting ambiguity the customer might have had.
Designing Perfect Text Field: Clarity, Accessibility and User Effort
Nick Babich
1K38
Maybe. But sometimes, it forces users into a format that is incorrect (for non-US numbers) or hard for them to read or remember.
You have provided a format example that does not work for many non-US phone numbers. Remember that most phone numbers in the world are not US numbers.