PluotSorbet makes it possible to bring J2ME apps to Firefox OS. J2ME may be a moribund platform, but it still has non-negligible market share, not to mention a number of useful apps. So it retains residual value, which PluotSorbet can extend to Firefox OS devices.
PluotSorbet is also still under development, with a variety of issues to address. To learn more about PluotSorbet, check out its README, clone its Git repository, peruse its issue tracker, and say hello to its developers in irc.mozilla.org#pluotsorbet!