They give a reasonable idea of knowledge of the language 'at that point in time'. Where many 'educators' fall down is that they might equate a result in a test with some concrete judgement about a child. My point here is that the meaning a teacher attaches to these results can have a very strong effect on a child. Concern, attention, help, yes. Sometimes it is hard.
Tests have their function.
They certainly aren't useless. Not enough yet, but the number is growing. Make good on the promise you made at graduation to keep in touch. My tongue is smiling.