The dynamic filtering option on the linked record field is very useful for restricting user choice when they are making a new link.
E.g. when linking a Contact to an Opportunity we can dynamically filter to restrict choice to contacts that belong to the same Client as the Opportunity does. Really useful.
What we can't do is filter a link from table A to B based on another link from table A to B, i.e. we cannot filter a Billing Contact link from Clients to Contacts based on which contacts belong to a given client.
This is a sticking point when creating relationships like the one listed above.