"Let's force the user to employ data-management best practices" is, for better or for worse, very much not the design philosophy of Excel. (More to the point, if you must consume the data that someone else produces, then you'd like very much to be able to deal with their less-than-best practices.)

Users really like to highlight rows, or use coloring to track their progress, or do some insane multi-color-mixed-with-other-formatting system to indicate complex statuses.

I’d like to be able to work with that terrible data.