It sounds like they're making an iSlapBracelet to me. That means the whole surface would potentially be a screen with just the part facing you being active.
I kind of wonder where else would be appropriate to wear it other than on your wrist, given that it explicitly mentions that (Geordi LaForge style visor perhaps?)
Depending on size of the band, strength of it 'closed' you could potentially wear it on your bicep like runners currently do with some iPods. I can't see it being moved off the wrist though, I'd assume appendage is to keep the language as broad as possible.
I think it's more just about covering the discrepancy between "child's wrist" and "adult's wrist". i.e. making sure the display doesn't try to render to a fixed size, when substantial portions of the 'band' may overlap.
I doubt they'd ship enough material to actually attach to a leg. And hopefully they're not just shipping an iSlapBracelet: a wrist computer needs to stay in place. Not spin around your wrist freely. Good luck to them in weighting such a device and getting it to stay in place.
According to the patent application, the slap bracelet is entirely covered with a flexible touchscreen. Sensors detect which side is facing the user. That way, it shouldn't matter whether the bracelet stays in place or not, the UI moves along with it.
Also, being a child of the 80s, I remember slap bracelets quite well, and in my experience, they fit quite snug and didn't move around much at all.
They also had no weight to them and what little weight they had was well-distributed.
Unless this hypothetical snap-bracelet device also had its weight very well distributed, it's going to tend to spin. Particularly if the total weight is sufficient to cause the snap-bracelet to slide toward 'open', even a bit, as your wrist rotates or travels through the air. And evenly distributing the weight over an entire-surface-screen would be quite a challenge, given the internals.
I think it more likely a production device along those lines would have a series of fixed potential-attachment-points and strong magnets to counter the forces caused by the weight of the device and movement of the wrist. And the screen wouldn't need to be over the entire device, but simply enough of the 'top' so that it could reasonably serve the various potential-attachment-point configurations. (the magnets would also provide a simple and consistent way to determine just how open or closed the device is)
I kind of wonder where else would be appropriate to wear it other than on your wrist, given that it explicitly mentions that (Geordi LaForge style visor perhaps?)