Screen-space reflections are faster and require no new scene draws, but they won't show you "new angles" on reflected objects and they won't go around corners. Planar reflections require a new scene draw, but that's actually pretty modest: non-planar reflections require six scene-draws for a cubemap or full on raytracing.
In general, lots of things in games require re-rendering the scene multiple times per frame, so game engines are really, really good at this. Shadows, projections, transparency / translucency, motion/depth blur, indirect lighting, deferred lighting, even things like hit testing (though for dependency + latency reasons that's a prime candidate for offloading to the CPU). Anything that requires less visual fidelity will have its performance tuned accordingly: fewer pixels, simpler shaders, lower LOD geometry, lower framerates. Nobody will notice if the fuzzy bounce lights are calculated once every five frames and blended.
Ray tracing is conceptually simpler but (so far) slower at any given level of cleverness -- you'll often hear that it has asymptotic benefits, but those same benefits can be pulled out of rasterizers with effort comparable to what is required to make the raytracing practical.
Here is a writeup of the passes you might expect to see in a modern engine: https://zhangdoa.com/posts/rendering-analysis-cyberpunk-2077
Here's an overview of a modern geometry pipeline: https://www.youtube.com/watch?v=eviSykqSUUw