Answer: The author's purpose is to state and argue how their opinion is greater.
Explanation:
The author's purpose seems like more of an opinionated argument than a factual article. For example, if a person argued that chocolate chip cookies are better than sugar cookies, then that would be opinionated. But if someone wrote about the history of chocolate chip cookies and sugar cookies, that would be factual because it would be stating true facts.
It's probably the author's purpose to argue about how their phone is better than an android phone, or however other way that this is stated.