DJD, by now you should understand what the purpose is and what it is being used for. I'll offer something you "might" need to be concerned with as I have seen mistakes made.
A lot of shunt trip coils can only handle being energized for a very brief period of time. You can wire in series with a normally open auxiliary contact if the breaker has one. The ground fault module may take care of this for you but I wouldn't assume so.
Personally, I'd pay and get a shunt trip coil that can handle being energized continuously (but only energize it until breaker trips). I see no downside (but there could be one I don't know about) and I would think it would last longer (but I may be wrong). Just make sure these get tested regularly as I have seen a good deal of failure on shunt trips. Certainly not my preferred way of doing ground fault protection. More like the right choice for an "emergency power off" button behind a glass door that gets used very rarely.