I would say these files are spacehogs by their nature, not by their size.
The same is true to the extensions I listed at the beginning of the thread...
So, why is .iso included, but not nrg? (just an example)
As I now understand the extension list in MyDefrag should only contain files that are kind of archives/backups, but not too likely to exceed 50MB.
This is NOT the case for .iso, .vob and .dvr-ms.
-Not only archives/backup but all files where placement does not matter much.
-You are right in that size limit makes some extensions redundant. The list does not pretend to be complete nor ideal, some items could be removed.
- OTOH size is not always good criterium for all files. It depends on access patterns.