Yeah, no. I guess when I said "access" it was a little ambiguous. I've spent way too much time sperging out about XBox regions on prior episodes, so let me clarify. Effortpost incoming!
On old X360, -some- games are region locked (about half of all titles) and you'll need an account/console/IP for that region. If you want, say, a non-region locked game from a different region, here's what you gotta do:
Make an account for that region. This is easy, do it through your web browser first though. (You can at least "access" the store at this step, meaning, just looking)
Add funds to that account (gift card code, or a credit card, billing address will be a hurdle though) -or- a download code for the game
Download that ****. It won't stall your download if it's not a region locked game.
If the game you want IS region locked, you're gonna need to do that stuff plus have a console and IP address for that region.
Now, accounts aren't region locked, insofar that you can load your profile and play on any system from any country on any IP address. If you try to download games you've already bought when you move overseas or the monthly freebies on games with gold, it will stop you or not stop you on a per-game basis. My NA account is well loaded with achievements from regionlocked JP games!
Now, on XBONE games and apps, there are basically no restrictions (unless, of course, you're downloading reverse-compatible X360 games, then see above not even on X360 games). You don't need a console from a specific region or a certain IP address, you can download any and all **** that's been added to your account. I've downloaded like a hundred NA region games on my JP IP address, put in JP DLC codes on my US region account+console, bought a bunch of JP physical copies. The system simply does not give a ****. Puyo Puyo Tetris, the uh, sole JP XBone exclusive isn't on games on demand for some reason, so I can't test purchasing it, but I just accessed the JP store and downloaded a Japan-exclusive app (ã‚«ãƒ©ã‚ªã‚±ï¼ DAM) and it worked fine.
So yeah, X360 is half-region locked, XBONE is region free. Accounts are global, but the X360 games on them my not be.