Note that if you use bass rolloff but increase the gain, you end up with just as much signal, just more skewed toward the treble and mids. So "you can't restore bass once you roll it off" isn't quite right — you might as well argue that rolling off bass is necessary because you can't restore treble that isn't recorded.
(And no, I don't generally use bass rolloff, but I also don't get the argument that it's discarding information, not when there's a gain setting right there.)