Well these are some of the benefits i can think of that storage pools have over traditional radi groups:  Storage tiering (FAST) ability to make pools with large numbers of disk for more spindle performance and IOPS. (RG's are limited to 16 disks.) abiltity to create both thick and thin lun's in pools  That is a few i can think of.  I am sure there are more.
Other than for future virtual provisioning purposes for what other purposes should we use disk groups vs raid groups in clariions? 
DISK GROUP vs RAID GROUP.