Google charts works so well because Google dominates so many other platforms that it is so much more user friendly to use google for all work aspects rather than switching back and form between platforms. Since you only have to embed the application, it makes using Google charts very simple and not time consuming to start. I am sure there are more advanced platforms that can do more with the charts, but for most people Google charts is more the sufficient in satisfying their graphing needs.
I spend a decent amount of time looking things up and how to do them. It would be great if it became more user friendly, or if google charts created a youtube account with videos on how to do things people generally have problems with. I think right now, people are used to using excel for creating charts. So it is easier to just use that and not have them done as well than to relearn a new system to do the same things.
I would take some time and play around with it to learn what all it can do before trying to use it for something important. Try to watch tutorials and videos online.
We use google charts to represent our data collected in experiments. In research, it is important to have simple, easy to read and understand charts and graphs, which can easily be made with Google Charts.