I had my house broken into this past year and was robbed a few months ago. I was only gone from the house for about 4 hours.
They took my 40" LCD TV. They took my Xbox 360 and all my games. Then even took my fscking Kelvin Kline cologne.
The one thing they didn't take? My desktop. It was easily worth more money than anything else I had, and in fact if you added up everything else they took, it wouldn't have equaled what my PC was worth (data and sentiment aside also).
Why? Because A) It is difficult and confusing for idiot robbers. There is a rats nest of cables plugged into everything that all need to be taken apart, and you need all the pieces. B) It is large and unwieldy (mine is even an ITX build!), big components, and multiple things to carry, and C) Ever bought a PC used or second hand? Not much of a market for it, and they are not worth much, particularly if you do not know what is in the guts.
If that was a Laptop, or a Tablet, or a Ultrabook (particularly anything recognizable as Apple) it would have been one of the very first things stolen. Easy to identify, easy to transport, easy to sell, worth money.
So there you go:
6) Theft Deterrent!
I think my next build will either be some super expensive system in a massive full tower case, or I'll find a nice bland beige box circa 1995 to put it in... Call it thievery camouflage...