I've been reluctant to sign up to the store. As I don't want any syncing to the cloud, it's unclear to me what's stored at MSs end, and what the repurcussions

I've been reluctant to sign up to the store. As I don't want any syncing to the cloud, it's unclear to me what's stored at MSs end, and what the repurcussions are from doing so. This seems a tactical way to get us to sign up for a store account.