Re: The problem is not trust, but direction
It looks like Microsoft have updated their T&Cs to be somewhat more specific.
Is it something off this :https://www.microsoft.com/en-us/privacystatement/
or http://windows.microsoft.com/en-US/windows-10/windows-privacy-faq
or http://windows.microsoft.com/en-us/windows-10/feedback-diagnostics-privacy-faq
The latter contains
'Full data includes all Basic and Enhanced data, and also turns on advanced diagnostic features that collect additional data from your device, which helps us further troubleshoot and fix problems. When devices experience problems that are difficult to diagnose or replicate with Microsoft’s internal testing, Microsoft will randomly select a small number of devices, from those opted into this level and exhibiting the problem, from which to gather all of the data needed to diagnose and fix the problem (including user content that may have triggered the issue). If an error report contains personal data, we won’t use that information to identify, contact, or target advertising to you. This is the recommended option for the best Windows experience and the most effective troubleshooting.'
Which seems to address the user log on credentials you might be specifying. Other items specify that dumps 'may' contain user data - this has been true for years, it's just now it's more obvious. It's the same under every operating system - if a process dumps core, it may well have user data in it.
So, yes, I'd anticipate it's for analysing issues. When a process falls over, there's no time to sanitise data.