This is also demonstrated in many of the samples, such as the Basic sample.
The down-side to binding on the Object rather than on a particular property of the data is that every time any Bindings are evaluated, all such Bindings to “” are evaluated, since GoJS cannot know which properties had changed. So there’s a performance penalty to using such bindings.
Also, as should be clear, since you have a TwoWay Binding, your back-converter will have to be more complex. The documentation for Binding has an example: Binding | GoJS API.