I use a different app to keep track of both my indoor and outdoor riding miles. When I ride Zwift I have to go to the website and manually download each activity I’ve done and then manually import it into the other app.
It would be nice to be able to select the completed activity on the companion app and download the data directly to your device.
For windows: all your activities is stored in your documents folder \Documents\Zwift\Activities.
Yep, I don’t have any issues obtaining the data, it just causes me to take an extra step. A button would be great 
What app are you referring to?
What app are you using. I use sportracks and golden cheetah and it take a few clicks to get all my data.
You can sync your \Documents\Zwift\Activities folder to google drive and you have all your data every were.
Cyclometer on iPhone.
Syncing to Google Drive isn’t a bad idea - I might try it, but it looks like it only keeps the data from sessions that were performed on that machine. Occasionally I have to use an AppleTV since the PC is shared.