Predicting 50% can be validated: if I say a coin will be heads 50% of the time, I know more than nothing: I know more than someone who incorrectly claims it will be heads 75% of the time.
And we can quantify in various ways how much better the 50% prediction is than the 75% prediction.
And we can quantify in various ways how much better the 50% prediction is than the 75% prediction.