I suspect they handed out Windows laptops / tablets, because they couldn't find an equivalent. It is very hard to buy a laptop without a Windows license and Linux "convertibles" just don't exist in the same quantity / quality of Windows ones.
Take the Surface / Surface Clone market, these devices really do make a difference to field workers, I have yet to find one that works as well with Linux. If you want your staff in front of the citizen (which you do for a lot of local authorities activities) then you don't really have a choice.
I can see from this fragmentation that support becomes more complex (your first line need to be able to do first line fix on Linux and Windows).
Another genuine question is, is there a good MDM for Linux? There are plenty of enterprise grade solutions for Windows.
I hate to say it, I don't think this one is Microsoft's fault lads and ladies.