The reason why I chose RTA is because the IGT is actually broken.

At the start of the game the IGT begins after the load That is where the RTA timer also starts

So how the timer is broken is this. In the beginning before the first encounter with the paper ghost the IGT is always running, weather you are in the Stats menu (Yin House, Archives, Diary, Puzzle) or the pause menu, it is always running.

After that first encounter the IGT changes to a different timing method the IGT will stop if you are in the pause menu or stats menu.

Another thing is if you die too, the IGT will revert back to the timing method of the beginning (timer always running in pause or stats menu)

It's really strange, So just to keep things accurate, runs will be timed by RTA. where I have the timer start and end is actually the same spot where the IGT starts/ends so it works out well. Also there is only one load in this game, and the timer starts after that load so no need to worry about load time advantages.