They'd have access to an asset that's highly valued, finite, and has the properties to serve as a future international reserve currency. It's a hell of a geopolitical "poker chip" to have fall in your lap.
It's not a unique opportunity in any way, if the German government somehow decided that it would be awesome to hold $2B or $20B of BTC, they can simply buy it at any time.
Right now. As the supply dwindles, the ability to supply that demand will decrease dramatically. If you got it for free in a seizure, there's zero downside to just hold it and forget it until later (when, ironically, the government sends your own fiat currency into a hyper-inflation event).
The government can simply print real money any time they want (or lean on the European Central Bank in the case of Germany). Why would they want to hold a useless tchotchke instead?
Because that "useless tchotchke" is going to be a life preserver for their government when the boat they've been shotgunning holes into the side of (their own currency) for 60 years finally sinks.
Yes, one day in the future we will find a use for bitcoin finally. It has been 15 years and we still don't have a really great use case for it but it will happen.
Sure there are plenty of use cases but no real significant traction for the everyday consumer. Price fluctuation is wild, would hate to have this has a "currency" that I hold to pay the bills. Even ignoring the volitility, the transaction costs historically have been high enough that it is not attractive from the consumer lens. Not FUD.
Deflation doesn't mean there's no incentive to spend. It means there's a slight relative reduction in the incentive to spend. You can argue that it's still bad, but it's a very different thing.
If the value of the reserve money is $2b one year and it deflates to $3b the next, does that mean you can print more fiat every year? Sounds like an attractive proposition to me
If you got the money with zero energy expenditure, you don't care what the current fiat market value is. It's like finding a free lunch sack of cash on a park bench.
You could argue that there's an opportunity cost to letting the money stay parked, but because governments ultimately dictate the value of their own currency, that point is moot.