It matters in brief periods of annoyance. If two kids are downloading the same 50GB GTA5 update, and two people are streaming netflix, and nobody gets upset, that's worth a few extra dollars to some people (not me)

Maybe you live alone or something, I have some days that will look like this at my place.

3 people remote working. 2 of them have streaming TV going at all times in their room. Then if the kids are home there are likely 2 other tvs going plus what they are doing with their phones.