In VR, some games make me sick, though most of them don't.
One of the worst was a roller-coaster simulator. What really did it, I think was the lack of g-forces. If you have ever ridden a roller coaster, you are probably familiar with the crushing feeling after the drop as you go back up again, I was, and braced myself for it. Except... nothing happened, of course, but it felt really weird. Even weirder when looking to the side, the acceleration is all wrong! I lasted about two minutes before getting sick.
I took some time to recover then tried again. Now, I did much better. I wouldn't say it was comfortable, but it wasn't to the point of wanting to stop immediately. But also, the immersion was broken, I went from "I am in a roller coaster" to "I am watching a 3D movie", which made for a pretty boring experience. To be honest, I enjoyed the first two minutes where I had to call stop more than the half hour or so that followed.
I am sure the same thing happen with the rope swings. Like a roller coaster, rope swings alternate between weightlessness and high g-forces, which VR obviously cannot transcribe. But if for some reason, your brain didn't expect these sensations, then no problem.
That's the reason I think motion sickness is a real problem for VR, even if you can deal with it. Because the way you deal with it is essentially by breaking immersion, but immersion is the whole point of VR. It also applies to non-VR immersive games to a lesser extent.
So, yes, I think it is something we should take very seriously, first by fixing the "bugs": low framerates, unnatural camera movements, etc..., by adjusting gameplay to avoid unnecessary motion sickness, and finally by providing accessibility features.
It is a bit of a controversial take, as it may seem "woke" or something, as if caring about motion sickness will make the experience worse for those who aren't motion sick. But it is actually the opposite! Fighting against motion sickness breaks immersion, even at a subconscious level.
The general idea is that motion sickness appears when the sensory experience is inconsistent, try to make the sensory experience as consistent as possible, both against motion sickness and for better immersion.