The answer here is very simple: you need them because SharePoint Server 2016 already ships with a built in language pack!
SharePoint without a language pack would not be usable as it would not be able show any text on any website. It would not know in which language to show the text. To ensure that our customers don't have to install a language independent core product and afterwards a language pack we always bundle our language independent SharePoint components with one language pack and ship that as our SharePoint Server 2016 installation bits.
You can (e.g.) have an english version of SharePoint Server 2016, a german version of SharePoint Server 2016, a french version of SharePoint Server 2016 and so on.
This can easily be verified on a SharePoint Server 2016 installation by looking into the layouts directory of an english SharePoint Server 2016 installation:
The 1033 directory holds the language dependent files for the english SharePoint installation. Additional language packs will add additional directories aside this directory (e.g. 1031 for german language pack).
So you always should install both patches, the language independent and the language dependent to ensure that the patch level of the language dependent files is in sync with the language independent core components of SharePoint Server 2016.