You must visualize RasterTileSetModel instances with view/tileset/RasterTileSetLayer. Raster layers are usually configured with the BASE LayerType, because they often show background data:

Program: Creating a RasterTileSetLayer with the BASE layer type 
const rasterLayer = new RasterTileSetLayer(model, {
  layerType: LayerType.BASE,
  label: "Earth imagery (Fusion)"
});

map.layerTree.addChild(rasterLayer, "bottom");

On the other hand, raster services such as WMS also support the notion of transparent raster data, which allows you to display multiple raster layers on top of each other: raster data that display roads or waterways, on top of a raster with satellite imagery, for example. Such overlay raster layers must be configured with LayerType STATIC or DYNAMIC, so that they can be placed on top of BASE layers.

When LuciadRIA visualizes raster data on a WebGLMap, it must have access to the data. See CORS problems when visualizing raster data on a WebGLMap for more information.