alt Hacker NewsPanama has done fine since a similar intervention.
The US didn't loot Iraq or Kuwait.
Trump is supremely transactional, so he doesn't do anything for free, but the high likelihood is that the US as a whole will spend more than it gets back in revenue, especially government revenue.
Panamá is doing "fine" because they actually own their fucking canal. If the US had its way and reestablished the Canal Zone, the rest of the country would collapse in on itself.
Which is exactly what they want to do with the Venezuelan oil.