Wall clocks use batteries nowadays, but some clocks in devices permanently connected to mains power still use its frequency - e.g. my Siemens kitchen oven, whic

Wall clocks use batteries nowadays, but some clocks in devices permanently connected to mains power still use its frequency - e.g. my Siemens kitchen oven, which promptly was off when there were some synchronization issues in the EU grid a few years ago. You'd think that in an appliance that costs several hundred euros, a quartz crystal wouldn't really move the cost needle, but as long as they can get away with it most of the time, why spend more money?