Hi all, sorry for the late response.
TMS (the company behind wpDataTables) doesn’t have any insight into the data that you save – you’re using your website’s database to store data, or you’re pulling data from external sources (Excel, CSV, Google Spreadsheet, PHP, XML, or JSON). You can allow people to add data to your tables on the front-end, and if you want to protect that data by allowing people to only see their data, you would be able to do that with the premium version of the plugin by enabling the “Users see and edit only their own data” feature.
It is also possible to add the %CURRENT_USER_ID% placeholder as a predefined filtering value for non-editable tables (which are included in wpDataTables Lite), so only the data of the currently logged-in user is displayed in the table.
As for the Google API – it is being used in the front-end as well as in the back-end. Google Charts cannot work without it, nor would you be able to create Google Spreadsheet-based tables without it.
Kind regards.