Re: Scarier than a gun?
17" blades are wakizashi, which are not difficult to draw. A long, powerful, Shinto period Katana of over 29" is considerably more difficult to work with, not only because of its length but also because of its increased weight and heft compared to a Koto blade.
Iaido does not teach speed, per se. A fast draw is fun to watch, which is why Inagaki and Korosawa incorporated it into their classic masterpiece films. The movie Western followed suit, with the 'high noon' scenario playing over and over again. But, like fast-draw in western movies, real life duels rarely came down to who could out-draw their opponent.
In IPSC the ability to re-holster quickly does little for you. Same with the ability to re-sheath a sword.
The Tameshigiri of the early 1800's was practiced on cadavers, not on live people. And the myth about blades cutting clean through machine-gun barrels likely originated with destructive tameshigiri, the breaking of swords, which came much later.
The proper cut is very difficult to master. I have been working on it for some thirty six years and have come to realize that, in the vast scheme of talent out there, I am still just a beginner who hasn't got it quite right yet.