Audio DSP has solved fewer problems than you might think. But this is also one reason I prefer ‘slicing’ to ‘segmentation’. Basically, the whole notion of detecting the end of a sound is just much trickier. For one thing, it’s not especially clear that there’s an obvious perceptual mechanism to try and mimic: I don’t think we’re often terribly alert to the moment when a sound stops, unless we’re concentrating on that particular thing.
IIRC the help file uses quite a small kernel size so that the time scales are pretty short, hence spiky. The bigger you make the kernel, the smoother the curve (but greater the latency). Novelty slice uses a pretty simple peak picker, just looking for inflection points where a sample is greater than either of its neighbours, which is basically [zl stream 3] -> [expr .... Offhand I don’t know what a minima in the novelty curve might denote, offset-wise, but it might be useful as a switch type of thing to start then looking for when the signal amplitude goes below some point.