It would be great to have a non-patent-encumbered simple file format that's supported everywhere. The fact that this is based on FAT32 might help adoption, everyone's computers can already at least read a BigFAT drive, and BigFAT support could be added at the application level for systems which don't support it at an OS level.
UFS2 might be the technically perfect tool for the job, but that doesn't matter when Windows doesn't support it. A camera manufacturer or SD card manufacturer can't start shipping their customers SD cards formatted with UCS2 when it's not supported by Windows. They could start shipping FAT32 SD cards and software and firmware which can read and write FAT32+BigFAT.
Straight from their FAQ:
We see emFile customers asking for solutions for bigger files. Implementing exFAT is not an option for us, as it is patent encumbered. SEGGER would need Microsoft's permission to implement and offer it, and our customers need to deal with Microsoft again to be able to use it in their products. This can be time-consuming and also expensive. We feel there should be a free alternative. The more popular BigFAT becomes, the better.
I guess using anything but FAT would make it hard for their developer base.
I already use FAT32 for some USB sticks when I need to be able to use them on various OSes without having to give it any thought, or for long term archiving.
This would be extremely niche but would have its audience. Heck, I wouldn't be surprised if HN readers adopted it just to taste the thrill of unlimited and obscene power.