That's a good analysis - maybe the difference (if there is one) is in terms of degree or openness. As regards theme park rides I haven't been on one for a very long time but can only cope with the less challenging ones. The motion isn't really the problem but being so high above the ground and feeling so exposed (even though I am safely strapped in) I find very scary. I could only manage the higher rides with my eyes closed. Even images on TV of someone looking our from a rooftop or cliff edge I find very unnerving but if they're looking out through a closed window it's okay. Overall I find motion enjoyable if it's at ground level or high up but safely "boxed in".