Great idea, but it seems like Facebook for your personal items. Brief look at the privacy policy:
However, if necessary, we may retain your personal information for our compliance with a legal, accounting, or reporting obligation or for archiving purposes in the public interest, scientific, or historical research purposes or statistical purposes.
...
We may disclose personal information to:
...
* our employees, contractors, and/or related entities
* our existing or potential agents or business partners
* third parties to collect and process data
...
In the old days this would be a pc "program" on a person's home computer and all this data sharing concern moot. Why this database madness? All that's needed is a simple encrypted cloud backup. Harrumph.
I think you're reading too much into that. All that means is that they can use other services to process your data, e.g. putting your data in an AWS managed database.