One of my Algebra 1 students just offered a suggestion for how to improve the website and app and I thought it was a solid enough idea that I figured I'd post it here.
He said that he and some of his peers get frustrated while using the website or app on their school-issued iPads and they accidentally press the "hint" button with their finger instead of the "check answer" button. This does legitimately happen to my students and it gets them somewhat upset because hitting that "hint" button ends their streak of consecutive correct answers and forces them to begin a new streak. I tell my students that their score for Khan Academy assignments in my gradebook is equal to their longest streak of correct responses (out of a possible 5 points if the exercise is five-in-a-row and out of a possible 3 points if the exercise is three-in-a-row).
My student's suggestion was that Khan Academy add a step where the website and app would ask you the question, "Are you sure that you want to use a hint?"