It's not about that. Lawful warrants can easily get confirmed by a local judge and the FBI can access the data via local prosecutors. That already works where the crime committed is very clear. It's more about cases where the US government thinks they need access but where the EU would disagree.

What are these cases that affect typical usage? And it’s not where the ‘US government thinks’. They need to show probable cause and get a warrant. Generally, when you get to that point, going from one developed democracy with fairly robust rule of law to another isn’t going to help.

FISA court rulings are usually accompanied by gag orders here in the US, under "National Security" flags... This means they'd likely be unwilling and/or unable to consult with a foreign, local law enforcement.

Not that I really agree with it, most of the time the secrecy is for secrecy sake imho, and to advantage government prosecution. It's pretty scary tbh. Does this mean it's ok for a US company operating in China to turn over US information?

None of this is really about FISA anything, so I'm not sure I follow.

But it could apply to an order by a FISA court as well? Just this specific case wasn't.

No, that doesn't make any sense. If you're doing something in the US that makes you the subject of a FISA warrant and your data ends up overseas, the people who are after your data have a party. This is all, of course, far afield from 'typical case' anyway.

What happened is roughly this: Pursuant a warrant, USG wanted something from Microsoft, Microsoft said it was on a server in Ireland and outside the reach of the warrant, USG and Microsoft went to court to sort it out. Meanwhile US Congress passed a law addressing situations like and mooting this case. That's it. In the grand scheme of things, this didn't really change anything.