They better be good for that 440 mp, and they definitely are not close to being as "spammable" as Rifleman with the flamethrower.
Their real cost is actually 360 or 380(haven't had enough coffee to do math to check it), so they are cheaper then obers, you're paying 60-80 mp for the ability to spawn them on the field, just like commandos are 350, but you pay 500 for them in commando doctrine #justrelicthings.