That's how I view it too. Diana having a full blown secret identity has never sat well with me; it seems unnecessary and against the grain of the character. She's not an American citizen, she didn't grow up here, and she came here to actively pursue a specific agenda (which is benign and positive, but still, she's trying to influence the country and she's got political ties to another nation and is not a American national, so it's a delicate thing). Why would she go to the lengths a secret identity requires? She's not a spy. She's here to be seen. The only real purpose it would serve her is to keep some of the people in her life out of danger.....but it's not like that really works either, just ask Lois Lane and MJ Watson.
A civilian identity is necessary just for day-to-day life, and that can be enough for Diana to go have a cup of coffee without being mobbed by people.
The support cast issue someone brought up is a legit criticism though. A lot of writers do seem to feel that not having a secret identity means not having a life at all. But that's not a problem with the concept, it's a problem with the writers.