If free users and paid users both have access to the app, then it's not a paid feature.
You just assert this as if it was self-evident, but it's not. The same feature can be offered for free and as a paid component of a package, just like the same code can be licensed to some under the GPL and to others under a proprietary license.
In this case, syncing is part of the service being purchased, and the means to achieve that is absolutely part of the package, even if it's also offered for free to others.
You just assert this as if it was self-evident, but it's not. The same feature can be offered for free and as a paid component of a package, just like the same code can be licensed to some under the GPL and to others under a proprietary license.
In this case, syncing is part of the service being purchased, and the means to achieve that is absolutely part of the package, even if it's also offered for free to others.