Mhh true, i skipped that part. Then, they might use tessellation and displacement for bigger/nearest details.
But, even though it’s really fast in newer cards, with tessellation you affect performances and introduce a lot of problems (ie. cracks, calculation of tessellation levels … possibly more…) that you will have to solve, so unless you want to have high snow or close camera angles, it’s easier and better to use only normalmaps maybe combined with parallax if you want more noticeable bumps.