What's the difference between a Timer and using a while loop?

[Perois2]

And what scenarios would I want to use each?

[Lepes]

Basically a while loop is a CPU time consuming task, it means your code is always running inside the loop.

A Timer uses internal chronos of your PC, if you program a timer for 1 second, CPU is free to do other tasks and when reach 1 second, your app receives a message that makes your code to be executed.

While loop says to the computer: "while this condition is true, do those instructions"
A Timer says to the computer: "Whenever a fixed time pass, call me"

Personally, If I can use a Timer, I won't use a while loop.