"Top coupling" in VHF bandpass filter
That filters has 4 sections, which if we number them 0 to 3 ...

0 is coupled to 1 by mixed coupling which is mostly inductive
1 is coupled to 2 by capacitive coupling through Cc
2 is coupled to 3 as 0 is to 1

Using all one type of coupling results in a filter with the shape tilted noticably one way or the other. Mixing the coupling type results in a more symmetrical filter.

Using a septum across the middle of the filter not only enforces capacitive coupling from 1 to 2, it also inhibits coupling of any type between sections 0 and 3, capacitive, inductive, or wave propagation. 

Filters are often made with a single coupling type when a canted shape is desirable, for instance when used before a mixer, steeper attenuation on the LO and image side is a useful feature.