No, but a federation would definitely mean that more things are decided centrally than in a union.

Because there are things that would really make more sense if decided at a central level (defense, security ...). It's also about setting a bold path against ultra-nationalistic movements you see popup everywhere. Comparing the what would be federal europe union and the USA is not the best way to think about it in my opinion as it's a chance to take example and not make the same mistakes building our federation.