Relatively speaking, a SoJ on classic is worth more in it's classic environment then it would be if it's exported to LoD, because in LoD there are better alternatives. In classic though, it's the high tier of currency. Plenty of people play classic Diablo 2 without ever getting their hands on a SoJ.
Though I understand if one only plays LoD, a SoJ in classic would not do you much good.
I dont really play classic but from using common since im sure everybody uses godly rare fcr rings over soj's to hit there fcr breakpoint and to obtain resist. But im thinking its hard to get your hands on an soj because everbody in a cs game are very greedy. That is the reason why its harder to get rich on classic than lod.
Only real use for soj's is for buffers like bo-barb or ench sorc, but they still retain there value for some reason.