Re: A Minor Quibble
"Because it's easy for Microsoft, and other web giants, to move files around the internet. One day, someone's messages and documents could be in Ireland, the next in California, or Canada."
No it isnt. That would breach the GDPR and cross security domains.
"And at all times, the data can be accessed by staff in the US."
No it cant. Microsoft has seperate security regions and remote access to data requires approval of a local data custodian.