no, you’re not missing anything… most operations in Rhino aren’t making use of multiple cores…
that said, neither are most other operations in other CAD programs or other types of software in general.
there are (relatively) very very few processes that lend themselves to CPU core saturation.
it’s fast and convenient and your computer is never bogged down.
i use Fusion360 for applying materials and rendering… they’ve made cloud rendering super easy in that program… you either click the render local button or cloud button to launch your render… and that’s it.
click cloud then a few minutes later, you’ll have it (and you’ll have it on your phone or you other computers etc.)
if you render at off peak hours / late night, you can sometimes get the finals back in a matter of seconds otherwise, yours will sit in a queue for up to 10 minutes.
my main reason for going this route is because i don’t only work at one desktop computer… i also use my laptop a lot and i really like being able to launch renders from it whenever i want instead of in the past, "i’ll have to wait until later to cook this in the macPro… overnight
so, for me, it’s speed and ease that is my determining factor in going this route…
i’ve seen better quality than Fusion gives but the tradeoff, in my case, is worth it.
five years ago, i thought we wouldn’t really be concerned with render times in 2018 but here we are… it’s going to be a longer wait than i imagined… i suppose real-time viewport rendering will be the best (and we can basically just take a screenshot) but i sort of gave up on that and will be using cloud for the foreseeable future.