As others have said, ketchup and tomato sauce are the same thing. Most of the time, the version of a product you get here will be just fine (if not better... no high fructose corn syrup!).

But there will be products where the local version doesn't match what you're used to, and they might not be things you think about ahead of time. My American parents are forever disappointed by Australian ranch salad dressing, for example.

This store imports US brands: https://usafoods.com.au/ It's expensive because stuff is heavy to ship across the world. But it's nice to have the option for occasional specific things you miss.