When we build a screen with the data in our sheet – we don’t always use all of our sheet’s columns. However, your app can still download the data in unprotected columns – even if they are not used or are hidden by visibility conditions.
If you have unused columns with sensitive or private information and your app is on a paid plan – you should make those columns protected columns.
When a column is protected, none of the data in that column can be downloaded. In the Data Editor, the column’s contents will be hidden and can’t be processed in any way by Glide.
If you have entire sheets that are not used at all by your app then you don’t need to protect them. Your app can only access sheets that the app uses.
For example – this Spreadsheet has four sheets, but the app only uses data from two of these (highlighted in blue). Because of this – our app will not download the data from any of the unused sheets.