People wonder why execs, not people with actual tech skills. I'll wager that for the military/government, this is not really about what skills those people bring in - it's about that accepting this role puts them under jurisdiction of
military justice, and suddenly all kinds of things that are business-as-usual when e.g. dealing with foreign powers, could become potential UCMJ offenses.
Call me conspiracy theorist if you like, but this looks to me like US Gov seeking to put a leash on the tech/AI companies, by tricking execs into getting personally exposed for things that would otherwise qualify as private business. Strategically, that's worth way more than just getting some FAANG engineers as part-time advisors.