Because people move to different countries.

There's no way to update the billing address of my US bank to a foreign address. My UK bank is in the address of my house there. My French bank is in the address of my house here.

As I said, you get one and only one guess as to how the company in question wants to handle this. I want to buy Minecraft for my kid's birthday. Do I buy it from the US store with my US card because that's where I lived when I set up my Microsoft account? Do I buy it in the French store with my French card (with that US Microsoft account)?

Answer: Both of those will get you permanently banned from buying Minecraft on that account. There's a Secret Third Answer, but there's no way of knowing it in advance (or even after the fact since there is no functional customer support that knows about this issue).

I’d not want to be responsible for the KYC/AML checks on your transactions.

Banks go out of their way for HNW individuals, which it sounds like you are with 3 seperate residences in 3 different countries, I’d check to see if you qualify.