See https://snippet.webix.com/nu3vxdff
The datatable with the flat, compact, and contrast styles shows vertical lines between columns. The material style should also include those vertical lines, or there should be a comparable style that does.
With large datatables, especially editable ones that may not be full of data, it is very difficult to identify the column you want without those lines. It makes it very hard to use the material style with large datatables.
Daniel Ethier