That's fine but how often do you export? How do you merge it with other exported data? Are you exporting your entire history every time? What about when Google/Facebook breaks their API or get rid of it?
That is why we are creating PrivicyPal -- to set a schedule to download and merge data from many sources and monitor over time. Will be adding beta testers soon.
As in, you can do GDPR export or Google Takeout now and then, but then you request it, enter your password/etc; in few days you will get a link to the archive. You can put a reminder to do it now and then, but then your export stales, it's just so frustrating. It's almost ok as a means of backup, but it's hard to use this data in a meaningful day.
See https://www.privicy.com/privicypal/about