I've never seen anything but 10^9 used for billions in the modern era, although it is in some >100 y.o. text books. Have you seen 10^12 in the wild lately?

Everywhere in Europe. Every European language other than English (that I know of) uses "billions" for 10^12 and something like "milliards" or "thousands of millions" for 10^9.

And to make things worse all the names after million are offset. Trillion, quadrillion, etc.

I often wonder why people don't use SI prefixes for money.

We could say that they've spent on the order of 10 gigadollars.

I really like the idea of using gigadollars in daily conversations.

I think everyone with English as Second Language got used to that difference. Especially in startup world, or country economics billion is an often mentioned quantity of money