Rendering Freestyle as preview in viewport, not only final render

Looks like the configuration and operation around Freestyle is stupid in case not offer in blender preview in viewport, but only in final render. Check this tutorial to see how many problems are in case no preview but only final render. youtube.com/watch

Want suggest to give option to Rendering Freestyle as preview in viewport, not only final render to see changes in options.

developer.blender.org/T97524 Differences betwen rendered view in viewport and render image and video