The other major one is reliability (but that is encompassed by sufficiently broad interpretations of "trusting NIST.") Also, for our specific application it's n

The other major one is reliability (but that is encompassed by sufficiently broad interpretations of "trusting NIST.") Also, for our specific application it's not clear how to assign precise timestamps to Bitcoin blocks that everyone can agree on; this is necessary to be able to use a beacon that is external to the block chain.