That alone makes this movie a must-watch, and a compelling reason it's survived as a masterpiece for well over two decades.
Beyond that, Ninja Scroll features fantastically rapid combat sequences, devilishly brutal tactics, some of the best Japanese voicework ever (the English dub is just hilariously bad, don't bother with it), a menacing musical score, a surprisingly complex story, and purely stunning animation throughout.
"Why did it need that H-scene?"
The directors even admitted 20 years later that there's no way around it: that scene was unjustifiable. Which is strange; I actually have no problem justifying it. But that's getting into spoilers.
Do be aware this tale is gory, bloody, nude-y, and sex-y. Don't go into it too young, please.
Again, this movie is absolutely fantastic. Can't recommend it enough. Do get around to it someday.
