To be fair, raytracing a sphere is easier than raytracing triangles. Even a single triangle is harder than a sphere, but with a triangle mesh you can't avoid t

To be fair, raytracing a sphere is easier than raytracing triangles. Even a single triangle is harder than a sphere, but with a triangle mesh you can't avoid thinking about acceleration structures and having a watertight intersection test, which includes worrying about floating point precision issues. So what you're saying may be less about raytracing vs. rasterization and more about spheres vs. triangles.