I don't understand this. What does the NSA get out of it? Developing it to study cryptography? Why not, but then why release it publicly? The fact that Bitcoin didn't replace fiat currency is something we know now, but recall that it was considered a possibility at the time. In the end, it just cost a lot of people a lot of money. Say what you want about the NSA, I don't think they would create something with a huge downside and no upside for them into the public for shits and giggles.
Pushes entities of interest towards using this new currency as part of sanctions evasion.
Creates downstream effects in tech for expanding the technology. Promising parts can be used to obtain budget for things that are even more off the books.
To this day one of the more prominent use cases of bitcoin/cryptocurrencies has been to turn USD into sanctioned currencies.