Clarification on naming conventions

Hello, I have a question regarding the Human (On the wiki called “Common”) naming convention and specifically regarding numerical suffixes.

The rules regarding human names state to " p _ ick a realistic name that could appear on a birth certificate with at least a first and last name._"

Does this mean adding a numerical suffix like the following , Firstname Lastname III, is allowed considering numerical suffixes do appear in real life birth certificates (An example of this being Barack Obama’s full legal name which is Barack Hussein Obama II) and if not, what is the reason for them not being allowed?

Thank you for your time.