Newer OS is the difference. If everything is running fine there is no issue. Eventually things may stop working on the older os but jellybean is still doing everything just fine. Reloading a box would mean finding an android os designed for the processor you have, and getting the load to take correctly- it's not for everyone. Is a chance of bricking when re-writing the os too BTW
Jelly Bean (4.1–4.3.1)
KitKat (4.4–4.4.4, 4.4W–4.4W.2)