Because Steve Jobs was afraid of dying:
“Ever since I’ve had cancer, I’ve been thinking about (God) more. And I find myself believing a bit more. Maybe it’s because I want to believe in an afterlife. That when you die, it doesn’t just all disappear,” Isaacson quoted Jobs as saying.
“Then he paused for a second and he said ‘yeah, but sometimes I think it’s just like an on-off switch. Click and you’re gone,” Isaacson said of Jobs. “He paused again, and he said: And that’s why I don’t like putting on-off switches on Apple devices.”