Probably because they're usually pretty dark inside, are tall, have many different floors that are easily accessible, and have almost perfect view in all directions if they're like the one in this picture.
I know the L96 is bolt action, but is the bolt_action tag appropriate to use in this image? According to Danbooru rules you're only supposed to tag only what you see, so I'd like to know what cues point to bolt action here.
Did you read the second part of this post? Just because you KNOW something doesn't mean the thing is visible in the picture. Which is what is needed for tagging.
