Hi Noseman,

To answer on a point of your video, when you join two edges of a surface, Moi create a new object with a curve type.
You could show it in the description frame : before joining you have 2 Edges and after you have a Curve.
This curve isn't a part of the object, you can move it to verify, it's not a part of the object, it's a new object.

Another possibility to avoid the "hard point" is to use the ReconstructCurve script which delete the hard points.
This script have to be use on a curve, here, you could use it on the joined curve (created by a join on the 2 edges).

At last, another possibility to delete the hard point is to delete it on the joined curve after a "Show Pts".

You have multiple choices...

Have fun