In short, Configuration nodes are used to parametrize workflow and appear in the component configuration dialog (the one that opens on F6 or double-click on a component), while Widget nodes are used to define interactivity in the workflow and they appear on the WebPortal/Interactive View (the one that opens on F10 or right click->Interactive View). So the functionality of the deprecated quickforms is split between these two new node categories.
Let me answer your questions one-by-one:
As far as i can tell I can only make a layout with widget but not configurations?
The layout of the WebPortal/Interactive View is fully customizable and is filled with Widgets only. The layout of elements in the component configuration dialog can not be modified in KNIME 4.0 and is filled with Configurations only. In this respect the situation does not change wrt deprecated quickforms, if you imagine a quickform as a combination of a new Configuration and the corresponding Widget.
Also widgets are only available in webportal while configurations are like the former quick nodes except you can’t specify an order? (And do they work on web portal?).
Yes, widgets appear only on the WebPortal/Interactive View, but Configurations correspond only to a fraction of old quickform functionality (quickforms appeared on WebPortal, while Configurations don’t).
I’m having trouble to see the advanatge of this change and how to use the new nodes over quick forms.
In the past quickforms served 3 purposes: parametrisation, interactivity and parameters in REST calls. These functionalities were split now between nodes
There will be a webinar on the new features in KNIME 4.0 on July, 25 and everyone is invited to join to get a better overview of how new add-on’s work: Events| KNIME