First of all, I love Scrivener. I bought it some time ago and have been using it for many different writing activities.
However, It’s annoying that some features available in the Mac version are not present in the Windows version and one of them, I’ve just found out, is the Sync feature. Why?
For a 5 dollars difference in price, it makes no sense offering a version for Windows with this kind of limitation. Actually, there shouldn’t be any difference at all.
Indeed, there are several differences at this time (mostly documented here). Having been a Windows user myself for a while, I fully understand your frustration.
But don’t despair! Item 5 on this post is the “official” answer to your question.
It takes a little time, but eventually they’ll catch up.
The main reason is because the Windows (and by extension Linux) version had work started after the Mac version. By the time version 1 for Windows was out, version 2 for Mac was released. They are working on bringing the 2 closer.
I have seen a number of features that I’d like as well. Just have to be patient. I have hopes that the 2 will have feature parity (have all the same features) at some point in the future.