Haha no problem, you are welcome!

Yes, there is a reason for not using IGNORE_ME. Imagine you call the function with
camera_follow(player);
from anywhere where my is NULL (f.i. the main function) or from any other entity that is not the player) instead of
camera_follow(my);,
then the code (on IGNORE_ME basis) will most likely not work correctly because the my pointer points to the wrong entity.