window.open(Xrm.Page.context.getServerUrl() + "/sfa/conts/edit.aspx?id=" + Xrm.Page.getAttribute("primarycontactid").getValue().id, "MyWindow", "toolbar=0,resizable=1,width=screen.width,height=screen.height");
The more interesting aspect of this command is the ability to pass parameters when opening the form (probably more apropo to the create form). This probably lends itself to creating a "clone" action for every CRM form among other more obvious usages.
The second function (openWebResource) is less obvious in terms of its usefulness - at least to me at this juncture. Perhaps it can optimize the performance for opening a form by not having to specify all web resources in the form definition that the form might use during the course of its operation and you can then manually load a web resource in the jscript when it is necessary? I'd be interested to see what the various use cases for this script might be.
Time to experiment and find out...