The TIE attack sequence, just like the droid factory sequence in AOTC, serves absolutely no purpose in the story;
It does have a purpose - it convinces the escapees (apart from Leia) that their escape was legitimate.
If you're going to cut it, why not cut the chasm scene in the Death Star? That serves no purpose to the plot. Come to think of it, the Podrace in Ep I is pretty superfluous. And what's all that stuff with Luke and the Wampa about in ESB? Pointless...
DE