Are you sure you are not confusing this with a sdcard swap file?
Caching will decrease SD life
Flash memory is degraded through write cycles and as this tweak adjusts the size of the READ cache from the sdcard I find it hard to believe that this would do any harm to the SD.
Do you have any info to substantiate this? I have had a brief search but can't seem to find anything. I would love to read any thread/article regarding cache size tweaks degrading sd life if you could share the links.
Edited by Cyda, 04 October 2012 - 06:37 PM.