Disclaimer I'm not UX expert.
Besides what @KentHawkings has already cited from Google's design guidelines (checkboxes for list of non-exclusive options and switch for a single option), there is a good (IMHO) use case for checkbox for a single option - when the checkbox clearly means yes/no.
Good idea for checkbox: "Show notifications" option.
Bad idea for checkbox: "Wi-Fi" option (as in Android Settings).
You could use checkbox here if this option was titled "Wi-Fi is enabled", but quite obviously "Wi-Fi" with "On/Off" switch is more concise.
Note that Play Market doesn't follow Google's own guidline - it uses checkboxes in its Settings all over the place.