I use GeoJSON all the time in mobile robotics. For indoor robotics, we are using our own local coordinate system. This means that we "lie a little bit" about the GeoJSON spec, treating x and y as linear metres in a flat world.
tl;dr: I would love if more tools allowed you to hide the map and just ignore the details of the CRS/Projection. I do so much work on and around Null Island as a result. QGIS has been _very_ good at this. But most online tools always assume use cases are WGS84.
Oh, absolutely this! I work on game heatmaps (Halo), player path analysis, etc. Having a flat-world coordinate system with a customer-supplied map is critical.
tl;dr: I would love if more tools allowed you to hide the map and just ignore the details of the CRS/Projection. I do so much work on and around Null Island as a result. QGIS has been _very_ good at this. But most online tools always assume use cases are WGS84.