This is a bonus/ additional perk from Vistana, which should be remembered is now separate from both *Wood and Marriott. The ability to use Star Options to stay within the VSN network should be totally unchanged, as the network is separate from *Wood.
Historically you could change your annual Star Options to Star Points ( although usually not a great deal) if you weren't able to stay at a VSN timeshare or exchange through II. I believe that this was limited to 2 out of every 3 years only. However, if you use Star Options and stayed in VSN properties you could conceivably have unused Star Options that would expire. I haven't read the T&C of this change yet ( or even the full email) but it seems on the surface that this is a potential improvement, in that you could now use those unused Star Options to stay in Sheraton and Westin hotels as well as TS properties ( albeit with a $130 admin fee attached).