Every piece of data on your computer that is owned by your user is available to any other app you run as your user. That's hardly unique to this data, and is a well known issue when it comes to personal data and the applications you run under the unix permissions model. That this is at least behind the "full disk access" control makes it more protected than something like all of the tax and accounting data your financial software is storing in your Documents or home folder (well, technically under macOS your Documents folder also has its own permission, but it's the same sort of thing where anything with permission to read from your Documents folder can read anything in there).

It's an eternal balancing act because every time Apple implements some new restriction in their OS that prevents apps from doing whatever they want, whenever they want, people get mad at them. But without those restrictions, the ever increasing amount of personal data that is stored on your computer is exposed to the ever increasing number of data slurping applications that you run.

> A permission that make apps ask for and others need to work (e.g. a terminal replacement).

I assume you mean 'many' and not 'make'—this is untrue; you only need to grant FDA if you're trying to access protected areas, like the knowledge graph store.

Granting full disk access to an app that you don't trust not to surreptitiously exfiltrate your data is the kind of user error where the buck stops with PEBCAK.