Ballistic missiles are easy to spot, after all they come over the horizon and don’t evade. Unlike us, the Chinese have been desperately working on ballistic missile defenses.
A hypersonic missile can come in at a much lower altitude and presents a much smaller window to countermeasures.
Only if you are expecting 1960's era warheads. Current warheads are maneuverable and include junk to spook defensive systems.
Simple maneuverability: Consider a cone, with the axis of rotation straight down the center. Slice the cone about one-quarter or one-third down from the tip, but make the cut line not parallel to the base. As the tip of the cone rotates, the body will no longer be axisymmetric. When this body re-enters the atmosphere, it will veer off a pure ballistic path. I'm sure that current warheads are more sophisticated than that.