I find this particularly interesting and, as with nearly all MS decisions over the last several years, it is part of their long-term plan to push their users into the the products and options that meet Microsoft's business plans, rather than those of the users.
Imagine you are a smallish business running Windows 8.1 Professional, with your PCs joined to a domain and managed by GPOs but not WSUS, as you don't have the resources to review and test patches. So, some PCs get the upgrade to Windows 10 and it's decided by management that they want to be on the latest OS so everyone gets upgraded to Windows 10 Professional during the free period. Fine, whatever.
But, one of your GPOs is set to disable the Windows Store and then one day the PCs get a new Windows 10 update and suddenly your GPO no longer works because Microsoft has decided to remove that option from Professional, confining it to the Enterprise license only.
You could get Enterprise but that's a big cost and requires license agreements that are out of your range.
Well, lucky Microsoft have a handy solution for you now . . .
And at that point you realise that MS have engineering their offerings and policies with the effect that you have to pay them a monthly fee to be able to control your own PCs.