Quote Originally Posted by Warsaw View Post
Think about it. If an alien species has interstellar travel, then they also know that energy is precious and that once you leave home, generally what you have is what you got. Why would these intelligent, space-faring aliens waste that precious energy on resource-expensive weapons when firing a bullet or missile as we do can get most jobs done just as easy? There's more to space travel and space combat than simply having fuel to get from point A to point B in a timely manner and having the biggest gun.
Think about this then.
If an alien species has travelled that amount of distance to remove us and put that much effort behind what they hope to achieve their not going to just dive in for a little fist fight, they will have no doubt researched us, what our abilities are what our weakness' are.
They are bound to have a much more refined efficiency in their weapons usage because as you said, they would know about their own limitations.
The problem is, the person who engages in a fight will usually win as they will have had time to prepare for what they want to do while the ones defending will have to take time to realise what is happening and what needs to be done to respond, time lost while the attacker can move forward in their plans.