That old clip shows a solo exercise and illustrates potential usage. Wayne's performance of the solo part of that old clip shows a lot of the handling skills and weapon control that were/are considered valid when using that metal weapon and I learned similar drills from various teachers. A very credible demonstration to my eyes.
Light metal weapons were the only things available in those days except to collectors. In training it is always good to work with a variety of weights and balances of weapon as it gets the hands and body used to not depending on a particular -- a favoured -- weapon.
Using just about any basic application with a broadsword would get you killed in a fight with weapons against a more experienced fighter, if that's all you've ever practised. Such "theoretical usage" if that's what you call a basic application is only a starting point for exploring two-persons sets and then free-style sparring. Even all of that is a pale reflection of real combat with broadswords; male fantasies aside, those fights and battles would have been more lessons in butchery than anything else.