On my last project, some joker took the (much maligned) paper file marked ‘Use Cases’ and gave it the more accurate title ‘Useless Cases’.
We hated that file. It contained so much misinformation, so many gaps.
Take heed though: Alistair Cockburn still thinks use cases are relevant.
We certainly learned on that project that while heavy-weight up-front use cases are a waste of effort, going into a sprint planning meeting with nothing more than a token for a conversation is also similarly irresponsible.
As Alistair says, the key is to get just the right amount of analysis done and no more, just in time. Finding that sweet spot takes practice, and lots of feedback within the team.