Unfortunately, Adobe requires that all illustrations done with Fresco be stored on their cloud service which gives you 5GB for free. There is no way to disable this and if you turn off your internet connection, it will resync your local files when you connect.

As well, this is installed through Adobe's manager which once installed is essentially impossible to remove without downloading an uninstaller from Adobe's website.

helpx.adobe.com/creative-cloud/help/uninstall-creative-cloud-desktop-app.html

If you're not ok with Adobe having access to your artwork, the bandwidth it needs to sync or Adobe installing an app that cannot be uninstalled without downloading an addition app, I'd avoid it entirely.