u can convert them to wbfs files if u want to keep your games permanenty that small
but if u just use WBM to transfer an ISO from one location to another, but keep the format in ISO, WBM will sparse the ISO for u, effectively having it take up less space on disc only, but if u copy that ISO from one place to another, it will go back to its original/full size. In my opinion WBFS files are much better, and they can be copied to/from anywhere and their size will not change.
As far as I can tell, by using the Wii Backup Manager, is auto. turn my Wii ISO to WBM files. Is there anything i need to do the setting of the Wii Backup Manger so I can make the newly made WBM files as small as they can be while still being playable?
Be nice if there is a step by step guide for the Wii Backup Manager