None whatsoever. There’s just a certain kind of internet denizen that has now decided that every war is World War 3, without exception.
War is bad. All wars are bad. Even when countries enter wars for good reasons, there’s still nothing good about the war itself. You don’t need some ridiculous fantasy about a regional conflict spiralling into a global one to justify why you think war is bad.
It, frankly, suggests a serious lack of concern for the lives of the people actually living in those regions affected directly by this. If the only reason they can seem think of as to why a war sucks is because it might eventually affect them directly, that seems like a pretty selfish worldview.
Within 4 weeks, the US will siege one of Iran’s islands in the Gulf. They’ll use that to control the flow of oil to Asia and Europe. This will cause a depression that the US will ride by printing dollars in exchange for letting oil through.
With that stranglehold, they’ll move on to Malacca and Nigeria within 5 years, in an attempt to corner the oil market and make the world fully subservient.
This might not cause a World War. But it should, and I think the odds are dire.