I think that the app is a bit misnnamed. I dont see it much of an assistant, but instead more of a (almost mathematical) reference tool.
Look up something like C Major scale, and you will be given the obvious information, such as the names of the notes in the scale, a drawing of it on a staff. But then you start to get into the less common info (alternate names, frequencies of the pitches in the scale, midi note numbers) and diving into the esoteric (results of various set theory operations).
As a music teacher, this is not an app that I would likely use. But, as a composer, some things are quite interesting. There is an almost encyclopedic set of scales that are fascinating to explore.
Some areas are very disappointing. The section entitled "Science of Music" turns out to be merely a tiny dictionary of a handful of technical terms, all with brief definitions that would teach little to the average musician. Likewise for the section entitled "Song Types." For instance, I would expect a definition of gavotte to speak more of the typical rhythms involved, and what a missed opportunity in that no examples were offered. I was surprised that this same section didnt have an entry for "gigue."
The interface is annoying at times. To look up a word, you must first identify its category (is it a style of music or a song type?), and then find the word in a picker menu. If you can not find the word, you may be left wondering if it is in another category.
It is also very limiting that you must have a web connection in order for the app to work. Frankly, I do not see enough information presented by the app to merit an Internet connection. The contents could easily be downloaded. And there does not seem to be any complicated aspect of the interface that would be served well by centralized processing.
This is not an app that I expect to use, although I might pick it up once and a while to explore its scales. I am not sure what Wolfram had in mind for this app. Perhaps they expect to grow the knowledge base online over time so that the app will evolve to a comprehensive knowledge source. In the meantime, Id recommend waiting before purchasing it.