Having rods in their makes people feel slightly less agile, as if the rods slightly limits the range and comfortableness of actions. Slightly though. Probably will not notice any hinderance to quality of life. Something related to "torque", though I honestly don't know what that word means, just heard it from another LL patient. If there is a screw sticking out possibly touching a muscle, then that limits your range of motion too. Overall this is a small issue, not a big issue. There is a user called Sweden here who has had his nails still embedded in his body for like 8 years or a number around that, and he has no problems. He has world class flexibility still. He did tibia 7cm.
Whatever the nail is made of, your blood will have slightly more of that substance such as chromium or titanium in blood levels. The nail is almost biologically inert but not quite. It will leak naturally. Across many years like decades, this is probably not that good. It is minor in the short term though. The levels are really not anything serious. But elevated metal levels in your blood is not ideal.
https://www.tandfonline.com/doi/full/10.1080/17453670810016911One should decide sooner or later however. As time passes the nail gets more and more consolidated into your bones natural structure. Let's say if 5 years down the line you want to remove the rod, it will be a longer and more arduous surgery than removing it now. One surgeon (Dr. Mahboubian) took 4 hours to remove two rods of a patient who kept rods in for 5 years. Probably the patient had to take a longer time to recover because the surgery was more traumatic. Not a big deal to be honest. Makes sense to just get the operation over with early on if you know you will remove it. But keeping the nails in is not really a big big problem, people have implants in themself all the time.