It is practiced more for microbreweries where they want to know when their brew is finished. This allows them to predict timings and to stop the fermentation with a couple of points gf gravity left so no priming sugar is needed for casks. They may do this for each new brew and yeast for regular beers.
For homwbrewers you would have to do this for every new brew or change of yeast and most would allow ample time anyway before stopping fermentation. The only situation I could forrsee this being useful is if you make a regular house beer and you are trying to cut this down to the shortest possible timescale.
