Dino Esposito describes an "historical" crud System in a series in msdn magazine https://msdn.microsoft.com/magazine/mt703431
This is basically ES with crud. Not saying ES with crud is the best example, but for data which requires Audit Trail logic it actually works fairly well.
Haven't read that article, but will check it out, thanks for the link.
My issue with audit logs in crud systems is that they're almost always at the row level, which is almost useless when you're trying to make sense of the audit log. An audit log of "operations"—i.e. command log—is far more useful, and trivial to implement when CQRS is used. I'm guessing that's what this article details...
(Edit: ok, they matter some, in the way names of variables and apis matter.)