No, who says that? Big three (Spanish, Scotch, Italian) is much better. Its perfectly playable of course.
Is the Ponziani Opening the best for beginers?

No, Ponziani is not an opening for beginners. It's only a temporary opening to trick beginners. If you want to learn and improve at the game, go with 1 of the big 3.

You can perfectly play Ponziani at your level. Its absolutely playable at your level, and at my level too. 2000s could also play it with not much issiue I am sure.
But if you are looking for the best of them (I am only speaking for e4 e5 here by the way, black has many more answers that you will have to play against it) I believe the other three openings are stronger. Spanish is probably strongest of them.
Is the Ponziani Opening the best for beginers?