Sorry smarty pants... but I figured this one out for myself! I wandered why this new white noise alert had become a thing because I heard of a similar concept being used by ambulances, but due to good old familiarity, it didn't take off. I coupled this with how difficult it is to find an old digital watch that's got buried somewhere in your bedroom and the only way you could find it is when the hourly chime or alarm sounded, and even then it wasn't easy to locate because single frequencies are hard to pinpoint.