In my estimation, it depends on your local raid group.
Have a fair number of decent people to raid with? Don't bother, as it likely won't net another ball.
Have just a few good players to raid with? By all means raise it, as it may make the difference between winning and loss.
As for usage; I don't foresee much utility through Gen 3. The only remaining legend weak to rock is Regice, but there are better counters out there without a doubt. As for returning pokemon; I don't see the legendary birds coming back any time soon, which was their original claim to fame. Would have utility against Lugia/Entei/Rayquaza, but all of the above have much stronger counters out there now.