I still respectfully completely disagree with this. If the fence is a problem with imperfect stock, then why are table extensions not a problem? To extend the fence logic: Why use the whole length of the board to get it level for a 90º cut when you only "want" to align the 90º bevel with the last foot of so?
But, no-one thinks like that because you have to have some way to support the board against gravity, yet it's the same kind of geometry. Fences make flip stops easy (unlike the above video that has these clunky large chunks that don't flip out of the way and heck, can't even be quickly removed from the T-Track). And if you really want to only align at the end of a warped board, just add a temporary spacer block to your fence.
Unless you are cutting 4X4’s that are perfectly straight, either a long straight fence or long straight outfeed tables are going to be a problem when working with un-straight stock.
Since we usually work with stock that has a rectangular cross section the stock it is easier to straighten one way than the other so it depends on whether the stock is upright or laying flat, which long straight fixture will interfere with un-straight stock.
My miter saw sits on top of the bench or table and this supports the stock so that the six inches or so that are critical relative to the joint are fully supported by the saw’s table and fence.
