This module contains two identical parts, either of which can be set to either sample and hold or track and hold by moving its jumper. By default, you get one of each.
I'm not aware of just how much sample and hold units can vary in quality, although this pair certainly does the job. When it comes to features, Doepfer comes out on top again, as track and hold units are certainly rarer.
Using (A-118) white noise as a sample input and an LFO as a trigger input, you can create the random LFO setting found on classic monosynths like the Roland SH and Yamaha CS ranges. Being modular, you can also put it to other creative uses. For instance, it can emulate the sound of a low fidelity digital sampler, akin to bitcrushing, with a sample rate you can dynamically tweak.
This is one of those small, basic utility modules (along with the A-114 ring modulator and A-150 voltage controlled switch) that are about as useful as you are imaginative. They can greatly expand the possibilities of your A-100 just as long as you can use them creatively.