Windows 10 adds a lot of value to the DoD. Better 2F authentication, better biometrics, stronger centralised control (e.g. Device Guard, all this[0]), VBS[1], and all of the improvements they missed in 8 & 8.1 (e.g. secure boot, improved Bitlocker, improved GPO/AD integration, improved security focused compiler technology, etc).

Plus the Enterprise LTSB branch is almost DESIGNED for the DoD (in fact I'd put money on governments being the primary target for even having a LTSB branch).

A lot of the complaints/criticism of Windows 10 doesn't apply to the LTSB as it has most of Microsoft's services stripped out from the get-go.

[0] https://blogs.windows.com/business/2014/10/22/windows-10-sec...

[1] https://technet.microsoft.com/en-us/library/mt601297(v=vs.85...