Using S&H with noise is common because it gives you a nice stepped-random, but you can use it on anything you like.
Here's a few ideas:
* Use S&H to sample a fast sequencer output slowly to produce a related slower sequence
* Use S&H to sample a LFO to get a stepped effect instead of smoothly sweeping whatever the LFO controls
* Use S&H on an audio signal triggered at audio rates (if the module can do so, not all can) for a "bit crush like" effect, except it's a crush in time resolution rather than amplitude resolution