Hi Dan,
I think you misunderstand the purpose of the MB Custom Table extension. It doesn't provide an Excel-like UI for users to enter the data (for that purpose, an extension with name "Data Table" might be a better idea). Instead, it save custom fields into a custom table in the database. So, in this situation, table means database table. The whole idea of the extension is changing how we save data: from post meta to custom table. That's it.