One of the reasons i buy this type of case is because i do mount my phone when i drive. The inner case is magnetic, so you can remove it in half a second and just stick it in your dashboard mount. Also with the inner case having a metal plate in it it is also compatible with magnetic dashboard mounts, you get the best of both worlds with these type of cases.I just assume that people with these types of cases don't mount their phones when they drive?
Also when i go running i can just put the inner case in my waist belt mounted case holder, just like i can with any other case.