But the written agreements are the "diplomatic agreements". A lot of things get said, a lot of positions get stated. It's the written agreements that are the actual binding promises.

Of course, as you say, those aren't really binding either. The written promises sometimes are worth the paper they're written on. Verbal promises are worth less than that.

Sure, but diplomacy it's much wider than dipomatic agreements and diplomatic agreements are just one tool of it that actually seems easier to be discarded than signed with informal communication shaping actual relations and tone way more.

Written agreements are usually cherry on top of the cake made entirely out of verbal promises and real world balance of force.