There are a great many video of individuals doing Tessen kata, and impressive looking forms at that, The thing is I doubt the Tessen was an Okinawan weapon, rather a Japanese weapon.
First let us look at one of those forms,
A version of the Shuri Ryu form Go Pei Sho using the fan.
Certainly looks impressive. Nor would I imply this is easy to do with skill.
I believe however the fan being used is more a heavy weight Chinese version of a fan.
And in the Chinese systems there are a variety of different weighted versions. Those for modern WuShu competition are extremely light to allow faster technique to be pleasing for the eye.
A more tradition Chinese use of the fan might look like this form.
Shaolin Steel Fan Demo
Notice the fan is used more with the motion of his form for effectiveness, where the Okinawan fan form he stops and flips the fans open and closed often, more for visual effect than serious fan use, IMO.
From my understanding on the Japanese battle field it was carried by the more senior combatants, who were probably running the battles. There was likely more than one type, but those used were to be used against swords trying to slice their heads off, They were much more durable, some even solid fans used as iron shields in fan shape, IMO
Of course is is also interesting that I cannot locate anyone from traditional styles using the Tessen either. In that I stand open to being corrected.
In all likelihood looking more like the above.
Over time change happens, but the reason change occurs is important to understand. Change just for dexterity exercise or for exciting completion is not bad, just different. But change does not equate to the original was something was used.
The more time moves forward the more things change.