This is huge to be able to track referrals. Real estate & service based businesses will be able to easily track what contact is associated with what contact. For example who referred who. I can easily look up based on the association how many deals a realtor has referred me. I know I can track this in other ways based on source etc. but I can go to a realtor or a borrower and have a list of all their referrals they have sent me. Or for service based business I can see how many customers are associated with this particular distributor. etc.

This is essential for workflows/segments conditions! (Ex only send a mail to only the associated (contact) of an object with a label instead of everyone at it)