Using SSD: What's the downside to normal redundancy?

Hi

Our environment is CRS 11.2.0.4 and 12.1.0.2 on Linux x86_64.  We've acquired EMC's XtremIO and are in the planning phase for transitioning our disk groups.  Our existing disk groups are redundancy normal.  Every EMC document and white paper is calling for disk groups of external redundancy as the best practice.  Our brief overview of the product explained that the de-duplication process employed by EMC means there's no actual copy of data, so normal redundancy serves no purpose.

However, they do not explain if there's a downside to retaining normal redundancy.  We have hundreds of databases now.  Relocating each one to new, externally redundant disk groups will call for outages and carries the risk of damaging databases.