It's so untypically cumbersome and unintuitive for a smartphone UI that to me it doesn't feel like a feature intended for end users. The button combination isn't always consistent from one phone to the next and afaik there's no way to know the right one without googling it or trying out a few variants. If you get the combination or timing wrong you probably changed some audio setting or locked the screen. Sometimes it's easier but in general it feels more like trying to enter BIOS settings on a random computer - it's basically the same procedure as entering a smartphone's or Surface Pro's bootloader menu.
