On one side, Russia has been calling their strategic missile forces "Space Force" for ages. In their case this is supposedly(*) just a name. So this move on the USA side is not entirely unexpected.
One another... If this announcement is not just marketing (as it is supposedly for now in the Russian case), this effectively takes out USA out of several treaties including the Outer Space treaty and moves the doomsday clock into seconds to midnight space.
(*)I am saying supposedly, because Russia and prior to that USSR has a long history of getting as far as prototypes for weapons which violate the Outer Space Treaty - Uragan, Polyus, etc