It really seems you have looked at the source of getopt but read the man page of some basic getopt of an old C library or something.

That would explain that you see undocumented features where everyone else sees a feature deficiency in your code

Switch clustering is a must-have. If you look at system utilities like ls, man, cp, tar, ssh,..., they all do it. Not that that is a reason in itself, but a consistent user interface is the holy grail of all interface design and a module going against that is simply not going to be used.