Once I showed this control to a few people they loved it and are asking me to make a lot of interfaces with it.
All of these are databound. 
They want some validation, like dropdown lists, datapicker, etc. And I found you can put controls in cells.
But what do I do with hundreds of rows? In the rows/cells there is validation and editors that can be setup.
For databound sheets, the columns would be a more logical place for validation and editors.

I did find this today, prepping for this request,  https://docs.telerik.com/kendo-ui/controls/spreadsheet/custom-editors

But that is not intuitive.

I'd like for the same validation and editors that are available on rows.cells to be available at sheets.columns when the sheets.dataSource is used.

These would be applied to the columns on the data rows created from the datasource.