"Is this (fingure jointed 2x's) another example of something
the carpenters of
yesterday would have used if it had been available? If so,
why?"

Of course they would have used them
They are straighter & stronger w/out knots.
Not that these guys were necessarily good wood lot managers
[ I suspect our fore-fathers of a lot of slash & burn
agricultural practices]
the short wood doesn't end up in the kindling/pulp pile.

DD