If your backups are encrypted and stored on a Google Drive account, there are no privacy issues minus Google knowing you are doing backups.

I wouldn’t personally do it, but I don’t see any issues with it if someone does this.

There are so many places to store data online. Just encrypt and upload it where you have space available.

AWS is cheap. Google Drive and iCloud are convenient. pCloud, sync.com, and any other online storage service are also great options. Just get your data offsite to avoid regional catastrophes.