My Take
I like this program when I teach transformation of functions. The algebraic functions and graphs can be viewed on the same scree at the same time. Also, each function and the graph are color coded to match. That is easy for students to make connections on different representations of function and it's graph.
Because of the visual of graphs, that is easy for students to make comparisons about how does the graph moved visually. And then I can let students make observations on the algebraic structure of each function and see how does that relate to graph changes.
How I Use It
when I teach transformations of functions, I like to use Desmos. I typed in the algebraic function or non-function and then the graph will come up, it also color coded.
Also I can use Desmos when I teach solving system of equations graphically. It can show the intersections of two graphs if they have one, or more or none.
I can use it for whole class instructions or I can let students to do group works and using this product to make their own observations.