How to use sharp edges? Well sorry if this one is a duplicate but i couldn't find it. Can someone please list the uses of sharp edges ?
I know the very basic uses like :


They can be used in edge split modifier.


But I can't think of more is there anything else that I miss?
AFAIK the only use for "Mark Sharp" is the edge split modifier. 

Technically "Mark Sharp" simply sets the mark where the modifier later has to do its job. If you don't apply the modifier, you can still add geometry with "snap onto itself" and "Automatically merge vertices" activated without having to manually edge-split the sharp edges later again.