Various treaties (which we usually obey) limit offensive weapons in space. You could use it for defensive purposes (such as missile defense) but are not supposed to use it to attack other satellites or other nations. It would still be legal to destroy satellites from the ground or air.

Of course, we still make plans. There were plans to send down tungsten rods if the Soviets tried to move their tanks through the Fulda Gap.

Most of the applications for space right now are less dramatic, but extremely important. As you mentioned, communications, situational awareness (spying), GPS, and weather sensing are all very important in the plan of battle. Someone taking out our satellites would leave us at a great disadvantage. Developing methods to harden satellites and protect our "fleet" is probably a big priority of the Space Force.

Note that I have no access to sensitive information on any of this. It is just speculation on my part.