With certain types of traffic, it is preferable to set a limit on the throughput of individual devices, instead of the network as a whole.
For example, with Netflix, it would be ideal to setup a rule of 768kbps for each user that is watching netflix. This ensures that they can watch Netflix, but not at a high quality that would hinder the performance of the network.
The current situation is such that we can only set a network-wide limit, which will only downgrade the quality of the Netflix stream if there are too many people watching netflix at once. In such a case, it is also possible to get so many people watching Netflix, that the global limit is no longer sufficient.
In more concrete terms, say that you've limited the Netflix usage to 10mbps. If only 2 people are watching, they will be able to watch at full HD (5mpbs each). if 20 people are watching, they will only have .5mbps each, which is enough for the bare minimum level (which is still acceptable for viewing). If 30 people are trying to watch, they will have less than the minimum required bandwidth for Netflix to operate, and who knows what the viewing experience will become. Theoretically, some of them will give up, freeing bandwidth for the others, but it leaves a bad tasted in their mouth either way, and is bad for student retention.
At 768kbps per client, you pretty much guarantee that they have enough for the minimum requirements (with some room to breathe), but yet prevent them from watching at higher qualities that would affect other applications (or in our case, cause overages on data usage). Combining the two approaches will also allow you to prevent Netflix viewers to completely monopolize the bandwidth, but that is less of an issue for us than overages on monthly data usage.
There are other applications like Skype and music/radio streaming where this could be handy as well.
For reference (regarding the numbers used above): https://help.netflix.com/en/node/306