That one happens to be true... but Fusion Drives (a hardware combination of a Flash Drive mated with a real physical Hard Drive that in software thinks it is one contiguous HD) are rare birds, found usually on high-end special order 27" iMacs and the occasional Mac Pro. I have two in my office. They are already hard enough to format properly so I can understand why there is a problem switching to a new file system.
They are even hard to partition or unpartition. I made that mistake unpartitioning mistake once. I won't do it again.
it is possible and Apple had them running in Beta Test, so they will get it going for those of us who have them, but I can understand why they aren't rolling it out with the general distribution. Thanks for the link. It lead to a better discussion article on Arstechnica UK which, unfortunately can't be posted or linked on FR.