It's a strategic investment for national security with net negative value.

The government does not want return of investment. The government wants to lose money so that national security gets better.

Maybe or maybe not in term of net tax revenue, but it's certainly an investment with an expectation of the preferred outcome of national security, with some portion of the subsidy maybe being returned as taxes of various kinds.

What? The government doesn't want ROI in the sense of increased revenues from selling IP, but it absolutely should be trying to maximise return (in whatever metric the elected officials deem appropriate) on investment. Just because something's not a startup doesn't mean value for money is irrelevant to it.

What happens to the local currency is just one factor in the overall considerations.

Investing money is different when you can create it from nothing. Needless to say the intuitions one develops from investing while not being able to create money at will are not entirely applicable.