For X seconds to do something for x seconds,
We need some things to happen for a period of time only but we need to use "everytick" for that and theese events slows the game.
For example : you need a text object to update the score for a few seconds only so that you can increment the score every y seconds by 1 to create an effect. Then what we need to do will be...
Create Boolean : "Incrementing"
Add event : Set Boolean "Incrementing" to true , wait for X seconds, set boolean to false
Add event : Every tick > if boolean true> Text Object > Set text to "Score"
Add event : Every Y second > if boolean is true > Add 1 to Score
Now this will work but with an unnecessary boolean and every tick event
Instead of this we can do,
For x seconds : Set Text to Score
For x seconds : every Y seconds > add 1 to score
Now there may be another way of doing this but this is just one example of the top of my head, there could be many more.
Plus it will save us unnecessary variables/booleans and every tick events.