Personally for apps like this, I'd like to see a confidence score with the prediction. I can deal with an inaccurate prediction so long as I know to add more buffer. Without that information, it doesn't matter how often the prediction is accurate, or how accurate it typically is, I must treat all of them as if they're the worst case scenario.
Same goes for things like weather apps or delivery or traffic or really any situation where the data is statistical in nature.