Slice and dice is a buff that you'll mainly use on longer fights than whatever leveling mobs you tango with or when you're in a fight with multiple targets flowing together so you go from one to one to one and you might opt to slice and dice rather than evisc for overkill.
edit:
eventually you get more methods of generating combo points so you won't be needing 5 activated skills to reach 5 pts and things are very different.