I track my weigth mostly daily, because it keeps me motivated. Today I "gained" 200 gramms, a normal daily variation, as long as it's not a daily/weekly gain over a longer time period.
Rather than telling me this is a failure and makes success even more sweet (rough translation of the German text, not sure about the english version) I would prefer the app say that it's a normal daily variation. For a good & healthy relationship with your body it's crucial to understand daily variations in weight are totally normal.