Spell speed allows users to "react" slightly faster to sudden spikes in damage such as misjudged timing of Regen, spamming your Cure II key and hope the heal lands on the tank before he dies etc (I know the everything is scripted, no reaction is needed bla bla bla, but I do not live in an ideal world where everything goes 100% according to plan ).

For Scholar however, you can react to these situations even faster via your Lustrates, and coupled with your Aldo's interaction with critical, you should choose Crit over SS anytime of the day.

As for your Last Resort's remaining 31 Stat points which I do not know what you put in....that may be a different story :P.