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.
Yes, I highly recommend the Ponziani openings. Look at this article. Its in https://chessbook.pro web app.
https://chessbook.pro/post/e47b98c1-b7cc-4ebb-a64d-59327e72dbb0
Yes, I highly recommend the Ponziani openings. Look at this article. Its in https://chessbook.pro web app.
https://chessbook.pro/post/e47b98c1-b7cc-4ebb-a64d-59327e72dbb0
way to revive 3 dusted threads on a sub-par opening for your advertisement 
Is the Ponziani Opening the best for beginers?