The thing about studs is, the threads in the block aren't "pulled" as much, since they are threaded in fully before torquing. Also, the studs are usually fine thread on the top bit, so the clamping force is better than coarse thread and they don't tend to loosen up as easy from vibration or whatever. Another plus is that any fatigue from re-use is mainly in the nuts, and they are easily and cheaply replaced. All that said, they are a pain to work with if you don't really need them.