When measuring a building or an area (wetland) users need to save the dimensions, area measurement and the polygon. Additionally this layer may contain useful attributes that are attributable to the parcel in which they reside.
From a user POV the building measurement layers could become "site sketches" used for assessment purposes and saved for years. When combined with recent airphotos users can bring in layer from years ago to compare to the recent air photo. Addional applications using this tool would allow assessors to sketch the buildings as a layer, and save to upload to the county. This would then provide the county with deatiled sketches and site maps of structures. The same could be done for measurment of agricultural use on a parcel .
It is time a sketching./measurement tool creates and saves a polygon in AGOL as it does in desktop.