If “all tests are green” it is either the day before deployment and anything non-critical has been paused, or the team is missing tests.
In my opinion, the primary use for permanently green tests is as regression markers - their greenness is an indicator that core function is working as expected.
If the qualifier is “all high priority tests are green” that’s acceptable. So is “all core function tests are green”.
An unqualified “all tests are green” tempts me to add a test that will always fail, just to prove that it’s not possible to have all tests green - or that it’s not worth fixing all possible problems.