The author of easyEmu stated this under the ClrMamePro section:

"What I did to sort out my rom sets was to run merger and select "Non Merged Sets" which created a set of roms with all the necessary files they needed to run in them. This used up 3.5GIG of hard disk space. I then ran scanner as if they were split sets and removed all of the unneeded roms. This left me with only split rom files and no merged ones."

My question is, what would be my motivation in doing as he says versus using the Scanner or Rebuilder? In other words, why would I do that to my ROMs using Merger? Thanks.