Melchett, stealth and hypersonic strategic systems are both sides of the 'bomber will always get through ' argument. Both can be used for first strike but only stealth platforms are reusable. Stealth systems also lose the surprise element for an attack on a continental size target set. This suggests that stealth is a better system if you expect to be engaged in a protracted war or against a smaller rogue State.
The utility of a non-nuclear strategic missile was always in doubt as your opponent might counter with nuclear just in case. The same logic could be applied to a hypersonic missile if you detected a massive attack.