A good point is made that on film or video, a realistic sword fight would be too short and too hard for the audience to follow. The sword fight in these media has many other purposes to fulfill other than being an actual sword fight.
I think, however, that film (or video) might be the best medium for depicting realistic sword fights.
On stage, the action would indeed be to quick and subtle to be understood by the audience. Film, however, can slow things down. Camera angles and distance can be chosen to clearly depict what is happening and focus on nuances.
Literature and audio drama aren’t good at depicting the details of motion for three dimensional combatants and their weapons. Film has a huge advantage there.
One place film is at a disadvantage—at least compared to literature—is in depicting the subtle feeling (fühlen among students of Liechtenauer) that allows a fencer to sense their opponent through the pressure of two blades in the midst of a bind.