I think it is good to inform depositors that both FDIC and NCUA are federal government agencies and hence will stand behind any losses up to the insured amount. If the losses exceed trust fund amounts, it will most likely be replenished with open ended taxpayer funds. Not doing so would take out complete confidence in banking system. This guarantee is certainly more explicit than the implicit support behind GSE’s that is attracting treasury and Fed support now.
In summary, splitting deposits to $100K and keeping it at the highest interest paying bank or credit union deposits is no less safe than treasuries and probably more profitable.