What interest does a government or large corporation have in cryptocurrency?

This is why cryptos as currently implemented will always be fringe and used for the most part illicitly, because as soon they gain a wide enough currency the participants in the system will switch to a more efficient, i.e. centralized system.

If enough people use them that a government or large corp would care, those "enough people" would form a new government or become the customers a new corp, that facilitates their transactions in a more efficient way.

...and a touch ironic that you seem to be pining for TBTF cryptos when Satoshi himself railed against the TBTF system.