Attached is an apple-to-apple comparison among Spectral Element Method (SEM), Finite Difference Method (FDM) and Finite Element Method (FEM). The accuracy achieved by FEM or FDM with 100 nodes can be achieved by SEM with 10 nodes.
In my opinion, researchers don't consider SEM just because of complexity in coding when compared with FEM or FDM. But when it comes to accuracy, no way.
Note: here I mean the low order FEM