The T-Mobile plan is limited to high speed in North America, and 2G elsewhere. Even when you pay to upgrade to 3G, it’s capped at something like 1/4 MBps. It’s borderline unusable internationally.
If you're in the Netherlands, KPN offers a 100GB EU+US plan, and T-Mobile offers a Unlimited NL + 10GB EU+US plan (although you should boycott T-Mobile [1]).
It's not quite the entire world, but it might be useful if you travel to the US often.