Imagen you would watch tv over linux mce, and then the door bell sounds... Linux mce would pop up a web cam image from the frond door on your tv, and you could talk to the person or you would be able to open the door right from your tv.
Or imagen, you are not there, someone would be at your door, he pushes the door bell button and Linux mce would tell him that noone is there but he could leave a massage (or even video massage if you got a camera there)
About keycards number codes e.t.c. would it be nice if linux mce could make a log, who entered when at witch door. (big brother is watching you, I know, but who knows when a function like that could be handy).
What do you think ?