Simple. Mango the Hutt doesn't actually care about results and actions, he cares about headlines, and with the attention span of an ADHD goldfish if you can get him off a topic he'll stop creating problems there.

So now he "has" his multi-billion headline but there's two key things to note:

1. It has not yet been signed off by the Ukraine parliament, they will (presumably) slow walk it

2. "Ukraine would retain “full control over its mineral resources, infrastructure and natural resources,” he said, and would relate only to new investments, meaning that the deal would not provide for any debt obligations against Ukraine"

Therefore the Yanks have to actually stump up new investment and generate profits before they get any money - and that's not terrible if they do (better half of something than all of nothing) but more likely nothing ever gets approved for investment (refer the bit where they retain full control), or the Yanks shake off the fascism and it becomes an actual positive relationship.

The whole thing isn't great, but if it gets the tangerine tantrum off their case and bullying someone else then that's good for Ukraine