Smart watches have been constrained (both function and aesthetics) by the form factor of the watch itself. There is only so much one can fit into a reasonably sized watch case. Sony has eased that constraint by putting some of the innards (that are normally housed in the case) into the watch’s band. The band is a great storehouse because: 1) it is physically connected to the watch and can therefore share functions; 2) There is room for a reasonable number of components; and 3) the band can be replaced when the electronics go obsolete. What a great idea!
This is a case (no pun intended) where a really obvious solution is sitting right in front of some of the most talented industrial designers in the world and it takes years for someone to see it. It makes you think about innovation and how we are unable to exploit it just because of the boxes we have built around the way we think about things.