When signing up for a free account it states that App Sheet is allowed to delete ALL drive files as well as spreadsheets. Concerning if it is across all accounts in a Google WOrkspace Domain.
That’s just the standard authorization window that you will see when logging into any 3rd party service using your Gmail account. It only lists the permissions you are granting, but not what the service (AppSheet) will/won’t do with this access.
AppSheet- as a whole, does need access to create/edit/delete all Drive files, because there is the potential for you to build an app that would want to do the same thing. But individual apps will only edit the data you connect and approve.
Once you grant this overall-access, that just gives AppSheet the potential to create/edit/delete files when you tell it to. You still have to build an app, connect a data source, and start processing data in some way before anything in your Drive would change.