exFat format can be used not only in SSD o pendrives but in standard rotary HDs.
This format works very well for multitrack audio recording/playback, better than NTFS.
Why exFat drives can´t be defragmented in offline mode or at boot time?
We have done some tests to make sure we support exFAT drives.
There should be no problem in defragmenting them at boot, you just need to disable any file filters.
We do not support any offline processing for any drive.