Do you mean, “The non-continuity (in reality) is what it is.” ?
If we kept the route relation purposely broken, wouldn’t this confuse a lot of other mappers? Because the first impression is, “This route relation is broken. It needs to be fixed.”
That was what happened to me. I was mapping the origins of a stream, and when I tried to upload my edit, JOSM validation checker warned me that the downstream portion (which was already mapped by someone else) crossed with WCE. So I created a bridge for that portion of the WCE and uploaded my edit and thought nothing more of it. The next day, other mappers commented that I had broken the WCE route relation. I was horrified! “Oh no, I better fix it fast before AkuAnakTimur gets upset with me,” I thought.
I spent a good half hour trying to “make the jig-saw puzzle fit” and just couldn’t. You can imagine my frustration when I finally figured out why (ie the non-continuity of the WCE is what it is in reality). 
Is there an OSM standard on how to map non-continuous expressways like this? Any idea how UK does it?