[flexcoders] Bindable Metatag

In the help file all the examples have [Bindable(event=change)] While the source files with FB3 have [Bindable(change)] Which is correct? Both?

[flexcoders] Bindable Metatag

I've read the docs but they left me wanting to know more! According to the docs I can add [Bindable] at the top of a class to make everything bindable. Fine but is there a downside to that or do I just blindly make whole classes bindable just in case or do I selectively make bindable only