Sometimes algorithms can be expressed far more elegantly in a tail-recursive form. The problem with that is the memory footprint, and possibly overflowing the stack. Though the 64bit JIT'er may sometimes decide to optimise the tail call, there are no guarantees, leaving you with no choice than to re-write the algorithm, avoiding tail calls. Having the compiler eliminate tail calls would let developers express algorithms in different ways, which may be more suited for the problem, while also helping developers who are not aware that their tail recursive algorithms may be problematic.