Re: In which case ..
It's not true block chain ... The key word being "distributed"...
The word "distributed" may be key, but it's no part of the word "blockchain".
The point about blockchains being "distributed" is that the people who invented Bitcoin specifically wanted it to be anarchic in nature, and not to require -- or be subject to -- regulatory oversight by any body such as a bank or government. Blockchain is the solution that they came up with to make Bitcoin transactions verifiable without putting anyone "in charge".
Now Microsoft apparently want to offer a blockchain-like "service" ... but if that's the case they're missing the point ... once Microsoft is in charge you don't need need blockchain because you have Microsoft in a position to provide regulation. Rather than basing transactions on a blockchain hash you can base them on the hash of a Microsoft Magic Cookie. Blockchain becomes irrelevant.
Unless, of course, you don't trust Microsoft ... but if you don't trust Microsoft why would you trust them to be the custodians of your blockchain?