They do seem a bit expensive, but somewhat useful. If there were some way of remembering the locations of planets, the long-range attack aspect would be even greater. You know, show what you saw in a system the Last time you had a ship there and don't update it until you have another ship or other unit in there.
The expense part might be limited by use of component enhancement by creating a mount that reduces the cost of each weapon type (including the catch-all of "none"). And, it'll be something the AI can use (and we mere humans can forget easily.)
