It's another way of adding intensity, similar to alternatives such as supersets, forced reps, cheats, negatives, etc. As with some other methods, it allows for a long time under tension to the muscle, considered a main ingredient for building muscle.
Main thing is whether it inspires you to use it.
To me it's gruelling, with no advantage over other means that appeal more, it depends on whether it appeals to the user.
IMO, the most effective use of super-slow is in doing an entire set of negatives only, using a weight that is too heavy to do in normal fashion-only the negative part of the motion is done. Another possibility is to do just a set or two of super-slow sets within a workout.