Bullet-time wasn't a visual effect, it was a story-telling device.
It had nothing to do with the actors, nor with the subject being presented. It was simply a way of moving the camera.
That's not so. The scene that made the nickname had parts captured from a camera array, and parts that were computer generated. There also were no actual bullets, those were CGI.
The ground-breaking thing they did was in the software that (a) generated a list of key positions to place the cameras, so they would have enough visual information (e.g. textures) to generate the scene with a minimum number of cameras and (b) software to create realistic scenes that were matched with the live action. The entire city and sky in that scene were CG by the way, they shot the actors on a green stage.
There were already camera arrays out there (I know this because I co-designed one of them in 1996), so the multi-camera thing wasn't the new trick here.
It could have been achieved in any number of ways. They chose [I presume the most practical] method of doing so, which can certainly be described as a visual effect. But that visual effect was in the method, not in the result.
What we saw was an actor doing what the actor did. Nothing was fake. It was simply filmed with many simultaneous cameras. That's not a visual effect. That's a filming technique -- no different than coloured lights and out-of-frame platforms.
Um, everything was fake, except for Keanu Reeves leaning backwards. In fact, they didn't even shoot that in real-time - he was on wires so that he could fall slowly. Their camera system didn't have the synchronization to be able to capture "simultaneously enough" to stop his motion if he had been falling at full speed.
Your second comment begs the question - what do you call a visual effect? Colored lights, arranging individual frames from several cameras as a motion sequence, fade to black, strobes, spotlights, filters? In my book, those are all visual effects. Some are more exciting than others, but they all affect the visuals.