DDJ400 to SX2 - Roll/Slicer: Are they useful?

I’ve recently upgraded from a 400 to an SX2 for the extra channels for deck input.
I mainly play House/Tech House if that’s relevant here and use an iPad Pro.
I preferred the 400’s pad setup for creating immediate loops on the fly so may remap Roll or Slicer to reflect the 400’s loop functions if I won’t be missing out. I’ve been reading up on and playing with Roll/Slicer but can’t really grasp their point. Do they have value or are they gimmicks?