Knowing the correct thing to do that will fix things (high IQ, e.g. making a vaccine), yet not doing it (low EI, like refusing to take said vaccine), leads to bad outcomes. Conversely, I've never seen anyone fired for being unintelligent (low IQ) who was willing to work with their employer (high EI).
Like making a nuke is great, but knowing when to use it - and more importantly when not to - is even better? And today's version: IQ resulted in climate change, yet will it now save us, or will we need to develop some EI as a culture or species to survive the massive issues facing our entire planet?
EI seems more mandatory to exist, while IQ... is great and fun and all, but not anywhere close to being on the same level. At least, that's what shows such as Star Trek taught me:-).
Maybe we can say that EI is necessary for longevity, while IQ provides more the spikes in processing power to get through a particular task in front of you. But even there, most tasks that people associate with "intelligence" have rather more to do with sheer dedication than anything else - e.g. math ability relates to patience to learn from constant mistakes especially those made early on prior to building up confidence, studies show. That patience helps you learn math, which literally makes you smarter (legitimately, bc it increases your capabilities).
Ergo even though intelligence is measured as IQ, it appears not to be a foundational but rather at least in large measure a derived characteristic for people. Which is why I was saying that EI trumps it: e.g. a genius who committs suicide helps nobody. But yes, locally there are times when IQ is more important, ofc.