I think this is pretty cool but what use could it be used for?
I didn't use this plugin, but ill consider this is a simplified kind of Observer (DP).
Imagine a shooting game where you get +10 for hitting enemies and -3 whenever you get shot.
So you have a SCORE: XXX label on top of your game, ok?
To update the score (the label, "forget" about counting the score itself) you can:
a) everytick draw the score (really bad);
b) set 2 actions on both "enemy hit" and "player hit" to draw the score;
c) whenever var_score changes, draw the score.
Approach b is still okish in this simple example, but imagine 10 actions changing the score or a whole differente situation.
Of course, using variables only is doable too, but this plugin sure is handy.