Why does `cabal configure` bother to create a `cabal.project.local` that only contains `ignore-project: False`?

[andreasabel]

What's the point of a cabal.project.local that only contains ignore-project: False? Why does cabal configure bother to write it (and possibly destroying the user configuration there, #8408)?

What is the point of ignore-project: False in a project configuration file anyway?
(It is like sealing the message "have this letter opened" into an envelope. Either you already have opened the letter, or you haven't opened the letter in which case you do not see the message. :-))