Shielded cable is almost exclusively used for audio circuits such as a mass notification or voice evac. Shielding (when done correctly) helps to prevent hissing and popping and other sources of interference from being induced on the speaker coil. I strongly recommend only using shielded cable when necessary and treating it with care when pulling. Yes, you could use it for SLC circuits and normal horn and strobe NAC circuits but it will cause you trouble in the long term with ground faults. I will also add that it is my opinion that shielded cable should not be pulled underslab if it can be avoided for the same reason. There are only a few other rare instances where shielded cable is necessary; like sharing a cable tray with Cat6a, and using it does not necessarily mean a better end product. Most trouble shooting nightmares start with shielded cable.