I agree that the only purpose served by the rod is to suspend the floor framing
However the bottom "chords" of the truss' are resolving most of the outward thrust of the roof (those collar ties are way up there)
The location of the floor beam down on the post below the plate means there is a lot of thrust on the post/beam conection
And it looks as tho some repair has been done with steel at the post plate conection.
Interesting...a little spooky...but interesting
