Legitimate use of EPO buttons
In the computer center the chief operator was an ex marine gunnery sergeant. In New Hampshire we always complained about the low humidity. The HVAC folks said they could fix this. The next moment the machine room started filling up from the bottom with fog. The operator calmly went to the EPO button and pressed it. It worked and he probably saved a lot of spinning rust.
When designing the operating system I had to debug the power off shutdown fault (meaning that there was 160 usec before CPU power dropped). There was just this time to save all of the essential state in core (yes, real core). So I sat powering down and up the main cpu - a huge monster - to test this. The field engineers were not happy as they said that the CPU wasn't designed for repeated power cycling but never had any problems.
So there are some legitimate uses for these buttons.