I want to take a slightly different track than talking about how awful the US healthcare system system is (and I can and do rant at length about it since I’m a former healthcare worker). One rare but significant outcome of fractures is that because bone shards are really sharp, they can sometimes nick or sever your veins or arteries. Part of keeping you “under observation” was to make sure you were in a place to get care at the speed you would need in the case this happened to you. Doctors (especially EM doctors) are trained to consider the worst case possible outcome and mitigate that.