Many of today's USB drive manufacturers default to exFAT as the file format to overcome the file size limitations associated with traditional FAT. While they allow their drives to be reformatted to NTSF - there are limitations associated with doing this
In particular some of the newer USB drives will connect to a computer, tablet, tv and phone (both iphone and android) allowing much for more fluid transfer / readability of files between devices.
exFAT supports this - NTSF does not.
I understand the original delay incorporating the file format since Microsoft kept exFAT proprietary for a number of years - but my understanding was the spec was published in 2019.
As tech continues to move in the direction of interoperability - it would be a real disappointment for Roku to have such a limiting factor associated with their TV's - especially when the TV itself really does provides an exceptional viewing experience.
Thanks for your consideration.