As they realized in Europe, Microsoft will turn data over to the US govt if requested, so using it on sensitive systems should be seen as a bigger security threat than some video app.

Yup, doesn't matter where the data centres are - a contract is only as trustworthy as the person or company you signed it with. Throwing all your government and medical and everything else docs on somebody else's computer with a "trust me bro" privacy statement seems like a recipe for disaster.