You don't have to loiter for all time.
That said, I'm thinking pumped-laser-tipped missiles could be very effective as e.g. anti-ship weapons. You could launch one straight up from your territory, and have it snipe the enemy ship from far away. The enemy would have to monitor a large portion of the sky for relatively small objects and react instantly with lasers of their own to counter that.
EDIT: I suspect these could be made into pumped-laser shells; good luck countering one that's launched from beyond the horizon.
True bolt-from-the-blue attacks are rare, though possible.
The spray profile could be modified to enable sensor detection, or alternative (off-ship, buoy, balloon, drone, ...) sensor placement could enable both eyes and shields.
More high, less ground.
https://en.wikipedia.org/wiki/Fractional_Orbital_Bombardment...
So: no.