Question re. auto-generated ccmp feature

Why does the ccmp feature add this line?

sub @Markscomb @Markscomb’ by @MarkscombCase;

Why convert a combining mark following a combining mark to a .case variant?

The case variant is usually smaller and if you type two that stack, the smaller variant would save some space.

Hmm. That’s a dangerous assumption. What if you were to design your UC marks quite different from the LC marks?

Is this something that people who work with combining marks normally do and expect? Because otherwise I don‘t understand how end users would even know this feature exists. I think that at this point it’s pretty well established that users don‘t read the readme file or pay attention to instructions in the PDF specimens.

I don’t think the user will be concerned about this.

Can you send me some examples where this would not be appropriate?