I use them all the time now. A firefight is more accurate and reliable, but comes with a much higher risk of catastrophic damage to your pawns. Mortars are a free attack with no risk, so I think it's a nice balance with their unreliability. There is the literal cost of making the shells, but mid to late game they're not that expensive.
So far, they work great for fallen ships and defending against siege attacks. Haven't used em to attack other bases yet, but I imagine they're worth it once you get launch pods.
So far, they work great for fallen ships and defending against siege attacks. Haven't used em to attack other bases yet, but I imagine they're worth it once you get launch pods.