We don't really know anything useful that can be done with quantum computers for civilization.

They can break some cryptography... other than that... what are they good for?

There's some highly speculative ideas about using them for chemistry/biology research, but no guaranteed return on investment at all.

As far as I know... that's it.

This is like asking whether $500 billion to fund warp drives would yield better returns.

Money can't buy fundamental breakthroughs: money buys you parallel experimental volume - i.e. more people working from the same knowledge base, and presumably an increase in the chance that one of them does advance the field. But at any given time point, everyone is working from the same baseline (money also can improve this - by funding things you can ensure knowledge is distributed more evenly so everyone is working at the state of the art, rather then playing catch up in proprietary silos).

What is quantum computing being used for?

No.