This would be useful if you want to set a variable hint. Suppose:
Question1: Select type object to inspect..
Question2: Calculate a target value based on question 1 (this question should not be visible; it's a calculation)
Question3: Inspection value with hint: "Target value is ${Question2}"
In the current situation of Survey123 Question 2 is obligated to be visible/relevant otherwise the calculation will not be executed. This is not desired because the user of the form does not have to answer the question.