How I Use It
In teaching, I would only use this for a student who might be really interested in words and meanings.It's similar to other word vocabulary, and could be good in a spelling station for students who need a chance to expand their vocabulary and decode words. Even at the beginner level though it may be too hard for many 4th graders because of the way the words are defined. It would not be appropriate for special needs students, especially at the elementary level.
This app would not make a very good teaching tool. It has very limited features. There's no way to track scores, no way to see how the words were picked or what lists they were from, and no way to choose from a variety of levels besides the default beginner, easy, medium, or hard. One doesn't know what each of those levels entails until they start playing the level. There is no reason for a student to want to come back to it time and time again. There's nothing flashy to catch their attention, no way to connect their progress or challenge friends. This app would also benefit from allowing teachers to customize and add their own lists. That way if the default levels are too hard, they can modify it to meet the needs of their students. Even then though there still would be nothing to keep the student wanting more of it.