Without an fstab you certainly won't have any auto scanning/loading of apps nor will the restore be automatic. It is true using the nofstab boot code does not imply dynamically created mount points.
But the claim that you cannot manually mount and restore/backup even with the gui is not the case.
Boot nofstab
You must manually create a mount point for the device, e.g., assume mydata.tgz is on hda1.
# mkdir /mnt/hda1
Then you must manually perform the mount, e.g.,
# mount /dev/hda1 /mnt/hda1
Once this is done, then using the filetool gui, enter hda1 to restore works as expected same for backup.
Using appbrowser, navigate to the your tce directory, if not already on the mounted drive, then you must manually make the mount point and mount the device as above. Then you must manually 'local install' the extensions. Not much fun to do it all manually.