I've never heard of 'Efilists', but I have definitely considered the notion that perhaps all life should end, in order to end suffering - and also ultimately rejected that notion on essentially the same grounds as you describe here.

Although I ultimately disagree with the Efilists and nihilists, I do kinda wish more people would spend more time deeply considering efilism and nihilism, as sort of an inoculation against being swept up in various forms of religious indoctrination and demagoguery. Most theoretical sources of value (e.g. blessings from gods) are just made up, and we therefore should be nihilists with respect to those values. We have to learn how to reject incorrect sources of value before we can reliably identify the true sources of value (e.g. feeling joyful and hopeful).