All of the file-sharing features are tied into "OneDrive For Business," which isn't OneDrive and is just some Sharepoint garbage. The new sync client helps a lot, but it doesn't work for the sharing part at all, which is what Teams uses. It's a huge liability for Teams until Microsoft can make OneDrive For Business not terrible. And when I evaluated it, it was missing any kind of snippet support, which I consider a dealbreaker (some workflows may not think this way, which is fine).