OK, now I'll wade in and then afterwards people can test out what I'm saying if they don't believe me. Microsoft has not helped matters by allowing the use of "Microsoft Account" synonymously between an actual Microsoft Account, which is what you use to log in on Microsoft.com, and a Windows 10 user account that is linked to a specific Microsoft Account.
Your Windows 10 user account that is linked to a Microsoft Account is wholly separate from that Microsoft Account. Since most people set up their first Windows 10 user account using the same e-mail address and password as the actual Microsoft Account to which they're linking this reinforces the false equivalence between the two.
Once you have established a Windows 10 user account, and a Microsoft Account to which that Win10 account is linked, you can change the passwords one either one of those accounts without affecting the password on the other. Your Windows 10 user account password is stored locally on your machine just like it always was while your Microsoft Account password is stored on Microsoft's servers like it always was.
Now, if you change the password on your Microsoft Account you will have to re-verify (essentially, recreate the link) the password for the Microsoft Account in the Accounts settings. The Verify button will reappear when Windows 10 detects that a given Windows 10 user account cannot log in to the Microsoft Account to which it has previously had an established link. You can test this out by changing the password on your actual Microsoft Account without changing it on your Windows 10 user account. I can assure you that you will still log in to Windows 10 using whatever password you've been using and will have to use whatever new password you've created for the Microsoft Account to log in on Microsoft's website and enter it in the Verify process.
The converse applies as well. You can change your password on your Windows 10 user account until you're blue in the face but it will have no impact at all on the password for your Microsoft Account. You also won't have to re-verify because changing your Windows 10 user account password does not break the link between an existing Windows 10 account and the Microsoft Account to which it's linked since the Microsoft Account password has remained unchanged and the Windows 10 user account is still using the correct credentials.
Someone could hack your actual Microsoft Account and it has no impact at all on your ability to log in to Windows 10 on your computer. These two accounts are entirely disjoint entities and it is just a "synchronization linkage" that exists between them. They are not one and the same.
(You can also prove this to yourself by creating a local account and then changing it to a Microsoft-linked account, or the converse, taking what already exists as a Microsoft-linked account and converting it to a local account via the "Sign in with a [local|Microsoft] account instead" link that's available on the "Your Info" pane of the Accounts Settings for a Microsoft-linked or local account, respectively.)
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story