Even with a 449 it is slower because of the extra pipe transition losing more time than 4IGT (which is the difference between optimal 5-3 and optimal 5-2) even without loads since w/o loads only removes the black screen and not mario entering the pipe and the fade to black in and out. Good idea tho, loses less for 24 runs because the extra complete black screen is removed.
There are not too many useful places for this (especially since low% 5-4 skip still seems unreasonable rta) so it is not really used in the category. If you could record yourself performing low% 5-4 skip than we could see if that could be used in runs, however for now it seems unreasonable not to mention the fact that there are very few places where a midair would even help.
about never playing it again...