I haven't used the software, but just took a look at the video.
My concern is that it asks the user to determine future portfolio returns and "seems" to assume that each year the portfolio will return the same amount. As you know, that isn't ever true.
I prefer to use tools that rely on either historic data, monte-carlo simulations or both.
I use ESPlanner which is I think is an excellent tool to do what-if scenarios. What if I take SS at 67 v/s 70; move to another state; downsize my home etc.