if the very same release is available in more than just one country (never mind their continents), that is enough to consider it an international release — but it’s still certainly not a worldwide release. there is a big leap between the two terms, and when people use the word “worldwide” it is often the case a slight marketing exaggeration, when what they really mean is international.
so for the sake of communicating information more accurately, we really should consider substituting the term “worldwide” with “international” or include the latter as a new option so that “worldwide” can remain an option for cases that genuinely deserve it. “international” has a broader meaning; it is factually correct for any release available in more than just one country to as many countries as you can imagine — and the best part is you don’t have to quantify the term. “worldwide” otoh, is a term one has to qualify; you either have to contend that a release is actually available in every conceivable country that has ever been known to be a market for purchased music, or you have to arbitrarily limit its meaning (eg, “3 continents”; why not 2? or 4?)
realistically, however, we would still have to set some kind of bar for which releases or vendors qualify to be deemed “worldwide”, so given the way our world works these days, i would say that “worldwide” should be reserved for just those releases you can buy as long as you have a credit card, or a paypal account or similar, and the vendor only cares that you have that, and not where you’re from. and that is why itunes should not be considered a worldwide vendor.
but if we introduced the “international” option, vendors like itunes would fit neatly in that slot, without editors having to then plug in every regional itunes store link and as many countries as they can manage, if only to convey the idea that a release is concurrently available in several markets without having to make or defend any claim that it is a worldwide release.