I assume in practice, filler words do nothing of value. When words add or mean nothing (their weights are basically 0 in relation to the subject), I don't see why they'd affect what the model outputs (except cause more filler words)?

Politeness have impact (https://arxiv.org/abs/2402.14531) so I wouldn't be too fast to make any kind of claim with a technology we don't know exactly how it works.