They never really stated it but I had to drag out of them what type of file it was about and since it's a Wii ISO I can only assume he intends to use it in Lakka or Switchroot Android. Can't do much with those in HOS
@PixyGixy If you just convert it to WBFS as I mentioned before (using Wii Backup Manager), the WBFS format supports splitting into multiple parts and Wii Backup Manager takes care of that automatically for you if you have it enabled in the settings, so size is not really a problem for Wii games. Dolphin can read the split WBFS files fine. I have yet to come across any cases where larger file sizes than 4GB are required for anything on the Switch. One possible exception being if you really like using the Switch to watch movies and you want to store full 8GB+ movie rips on the Switch but honestly I've not seen a single person asking how to do that yet so it doesn't seem like that's something anyone actually uses their Switch for. Otherwise there are always ways around the 4GB limit.