Screen space is definitely used in a lot of games, but it’s not the sole contributor to reflections in the scene. You’ll want to use Reflection Capture Actors in your scene as well to help give an ease to the transition. The biggest factor with using SSR though is that you want to add some roughness to the material so that the transition between the reflection capture actors and SSR is not as easy to notice.
This is where 4.12 comes in and will offer a new type of reflections with Planar Reflection Actors.
Here is a comparison of SSR on the right and Planar Reflections from 4.12.
This is just a limitation of using SSR that you have to find ways to mask it. With Planar Reflections, even though there is an additional cost to using them they can provide a much better result for your scene when you have a need for very reflective surfaces.