But was it worth sacrificing the best image possible to do that? Think about past the initial times you use it. Every co-op playthrough, every speed run. You're at 1328x1080p primarily because of instant switching.
I played through the original Halo 2 campaign over 10+ times from start to end, done it twice on legendary. I personally don't need to see how it looked at this random structure in 2004 instantly. I'd rather have taken the higher visual fidelity, and kept the original campaign as a menu toggle or something.
Do you play the Wind Waker HD remake, and think man, I wish I could switch back to see it how looked in 2002 instantly as opposed to having it look the best it can. Probably used the switching feature less than 10 times in CEA and didn't do it again. Now with updated audio as well, why would I really want to keep switching back to classic Halo 2, and not only see a worse picture, but hear worse audio?