I am wondering, why do you put the condition in the tick ? isnt it too much heavy for the machine to do by this way ?
Instead of doing this each frames, i purpose to do it when the trigger is activated or deactivated, by this way, the action will be called only one time and not each frames.
This is a simple approach and while other approaches may seem simpler, triggers, collision and the likes still have to detect entry and exit of bounds. These processes will perhaps be a little optimised but is basically the same code, running on a tick event somewhere.
I did ask the instructor about this and his answer was that this is a nice simple approach and for this course it is the easiest way to deal with it.
For smaller projects like this, it is fine. You may choose to tackle this with overlaps but it is a perfectly valid approach.