The sniper concept is one of deterrence. That area is a key artery for DC and VA. Given the state of the world abd that the enemy is now within, I’m not opposed to it. There are snipers on the roof of the Capitol and other DC govt buildings and in years past for certain events there were snipers on the roof of the Kennedy Center which is right across the river in DC from the proposed arch. It’s the cost of doing business in the Capitol.
It would be an excellent platform for a direct energy weapon.