I want to suggest add the functionallity of search with Projected Coordinates on World Geocoding Service. It is usefull to find on a Search Tool with WebAppBuilder Applications.
The format will be similar like the url paramenters for WebAppBuilder (Usar parámetros URL—Web AppBuilder for ArcGIS | ArcGIS )
Example
With Decimial Degrees
-84.35,10.25
With Projected Coordinates
298235,1138407, 5367
x,y, wkid
Thanks.
.Karol Fallas Corrales